Tracked vehicle and chassis therefor

ABSTRACT

A tracked vehicle with a chassis comprising an upper frame structure connected to a lower frame structure, the lower frame structure spanning a longitudinal distance along a longitudinal direction of the vehicle, wherein over a first portion of the longitudinal distance, the lower frame structure overlaps with the upper frame structure and wherein over a second portion of the longitudinal distance, the lower frame structure does not overlap with the upper frame structure. The tracked vehicle may also comprise an operator cabin, power plant mounted to the upper frame structure and a plurality of track assemblies for traction of the tracked vehicle. Each track assembly is o mounted to the lower frame structure of the chassis and comprises a drive wheel; an end wheel; and a plurality of support wheels therebetween; and an endless track disposed around the plurality of wheels for engaging a ground on which the tracked vehicle travels.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. application Ser. No.15/574,863 filed Nov. 17, 2017, which is a National Stage ofInternational Application No. PCT/EP2015/072138 filed Sep. 25, 2015,which claims the benefit of U.S. Provisional Application Ser. No.62/173,990, filed on Jun. 11, 2015, which are hereby incorporated byreference herein.

FIELD

The invention relates to tracked vehicles designed to travel on variousterrains, including rugged terrain, for example, tracked utilityvehicles carrying work equipment.

BACKGROUND

One type of tracked vehicle is a tracked utility vehicle, sometimesreferred to as a “tracked carrier” or “tracked equipment carrier”vehicle, which carries and enables use of work equipment, such as acrane, an aerial device, a drill rig, a digger derrick, and/or any otherindustrial apparatus, on various terrains, including rugged terrain(e.g., with mud, steep hills, swamps, rocks, mud, and/or snow).

It is often desirable for a tracked utility vehicle to have a carryingcapacity as large as possible but yet be sized such that the vehicle canfit a public road infrastructure. For example, it may be desirable thatthe vehicle be low enough to fit below an underpass or otherwise respecta vehicle height limit of the public road infrastructure (e.g., whentransported on a truck's deck trailer). This typically imposes certainlimitations on components of the vehicle. For instance, this may limit asize of a chassis of the vehicle, to avoid interference of the workequipment with public road infrastructures (e.g., bridges) or tootherwise respect the vehicle height limit of the public roadinfrastructure.

Moreover, it may also be desirable to facilitate the installation of thework equipment onto the chassis of the vehicle.

The work equipment carried by a tracked utility vehicle is normallymounted to the vehicle's frame. This can often present issues orchallenges. For example, the work equipment is often designed to beinstalled on a truck's frame. Since the tracked utility vehicle's frameis typically very different from a truck's frame, the work equipmentcannot be mounted as readily to the tracked utility vehicle's frame thanto a truck's frame. Rather, modifications may have to be made to thework equipment and/or to the tracked utility vehicle to allow the workequipment to be installed on the tracked utility vehicle's frame. Forinstance, in some cases, an intermediate support structure may need tobe installed between the work equipment and the tracked utilityvehicle's frame to support and anchor the work equipment.

Challenges similar to those discussed above in respect of a trackedutility vehicle may be encountered in other types of industrial trackedvehicles.

Accordingly, there is a need for improvements in tracked utilityvehicles and other tracked vehicles.

SUMMARY

In accordance with an aspect of the invention, there is provided atracked vehicle.

Accordingly, there may be provided a tracked vehicle that comprises achassis comprising an upper frame structure connected to a lower framestructure, the lower frame structure spanning a longitudinal distancealong a longitudinal direction of the tracked vehicle, wherein over afirst portion of the longitudinal distance, the lower frame structureoverlaps with the upper frame structure and wherein over a secondportion of the longitudinal distance, the lower frame structure does notoverlap with the upper frame structure. The tracked vehicle may alsocomprise an operator cabin mounted to the upper frame structure of thechassis; a power plant mounted to the upper frame structure of thechassis and comprising a prime mover; and a plurality of trackassemblies for traction of the tracked vehicle, a first one of the trackassemblies being on a first lateral side of the tracked vehicle, asecond one of the track assemblies being on a second lateral side of thetracked vehicle. Each track assembly of the plurality of trackassemblies may be mounted to the lower frame structure of the chassismay comprise a plurality of wheels including a drive wheel; an end wheelspaced apart from the drive wheel in the longitudinal direction of thetracked vehicle; and a plurality of support wheels arranged between thedrive wheel and the end wheel; and may also comprise an endless trackdisposed around the plurality of wheels for engaging a ground on whichthe tracked vehicle travels, the drive wheel being in driving engagementwith the endless track to impart motion to the endless track.

There may also be provided a tracked vehicle that comprises a) a chassisextending in a longitudinal direction of the tracked vehicle; b) anoperator cabin mounted on top of the chassis; c) a power plant mountedto the chassis and comprising a prime mover; and d) a plurality of trackassemblies for traction of the tracked vehicle, a first one of the trackassemblies being on a first lateral side of the tracked vehicle, asecond one of the track assemblies being on a second lateral side of thetracked vehicle. Each track assembly of the plurality of trackassemblies may be mounted to the chassis and may comprise a plurality ofwheels including: a drive wheel; an end wheel spaced apart from thedrive wheel in the longitudinal direction of the tracked vehicle; and aplurality of support wheels arranged between the drive wheel and the endwheel; and may comprise an endless track disposed around the pluralityof wheels for engaging a ground on which the tracked vehicle travels,the drive wheel being in driving engagement with the endless track toimpart motion to the endless track. The chassis may have a first portiondirectly under the operator cabin and a second portion behind theoperator cabin in the longitudinal direction of the tracked vehicle, thefirst portion being structurally reinforced so as to provide a greaterresistance to torsion than the second portion.

There may also be provided a tracked vehicle comprising: a chassis witha lowered portion in which a torque box is received; an operator cabinmounted to the chassis; a power plant mounted to the chassis andcomprising a prime mover; and a plurality of track assemblies fortraction of the tracked vehicle, a first one of the track assembliesbeing on a first lateral side of the tracked vehicle, a second one ofthe track assemblies being on a second lateral side of the trackedvehicle. Each track assembly of the plurality of track assemblies may bemounted to the chassis and may comprise a plurality of wheels including:a drive wheel; an end wheel spaced apart from the drive wheel in alongitudinal direction of the tracked vehicle; and a plurality ofsupport wheels arranged between the drive wheel and the end wheel; andalso having an endless track disposed around the plurality of wheels forengaging a ground on which the tracked vehicle travels, the drive wheelbeing in driving engagement with the endless track to impart motion tothe endless track.

There may also be provided a tracked vehicle comprising: a) a chassiscomprising an upper frame structure and a lower frame structure; thelower frame structure spanning a longitudinal distance along alongitudinal direction of the vehicle; over a first portion of thelongitudinal distance spanned by the lower frame structure, the lowerframe structure overlapping with a first section of the upper framestructure; over a second portion of the longitudinal distance, the lowerframe structure overlapping with a second section of the upper framestructure, the second section of the upper frame structure comprising atorque box; the first and second sections of the upper frame structurebeing secured to the lower frame structure; b) an operator cabin mountedto the chassis; c) a power plant mounted to the chassis and comprising aprime mover; and d) a plurality of track assemblies for traction of thetracked vehicle, a first one of the track assemblies being on a firstlateral side of the tracked vehicle, a second one of the trackassemblies being on a second lateral side of the tracked vehicle, whereeach track assembly of the plurality of track assemblies may be mountedto the chassis and comprise: i) a plurality of wheels including: a drivewheel; an end wheel spaced apart from the drive wheel in thelongitudinal direction of the tracked vehicle; and a plurality ofsupport wheels arranged between the drive wheel and the end wheel; andalso an endless track disposed around the plurality of wheels forengaging a ground on which the tracked vehicle travels, the drive wheelbeing in driving engagement with the endless track to impart motion tothe endless track.

In accordance with another aspect of the invention, there is provided amethod of installing a torque box on a tracked vehicle.

Accordingly, there may be provided a method for installing a torque boxon a tracked vehicle, the tracked vehicle comprising a chassis extendingin a longitudinal direction of the tracked vehicle and a plurality oftrack assemblies for traction of the vehicle, a first one of the trackassemblies being on a first lateral side of the tracked vehicle, asecond one of the track assemblies being on a second lateral side of thetracked vehicle, the method comprising: placing the torque box within alowered channel defined by side walls and a frame structure of thechassis; and securing the torque box to at least the side walls.

Also, there may be provided a method for installing a torque box on atracked vehicle, the tracked vehicle comprising a chassis extending in alongitudinal direction of the tracked vehicle, a plurality of trackassemblies for traction of the vehicle, and an operator cabin mounted tothe chassis, the method comprising: without removing the operator cabinfrom the chassis of the tracked vehicle, securing the torque box to areinforced portion of the chassis under the operator cabin and to alowered portion of the chassis behind the operator cabin.

In accordance with another aspect of the invention, there is provided achassis for a tracked vehicle.

Accordingly, there may be provided a chassis for a tracked vehicle,comprising: an upper frame structure; and a lower frame structureconnected to the upper frame structure, the lower frame structurespanning a longitudinal distance along a longitudinal direction of thetracked vehicle; wherein over a first portion of the longitudinaldistance, the lower frame structure overlaps with the upper framestructure and wherein over a second portion of the longitudinaldistance, the lower frame structure does not overlap with the upperframe structure.

Also, there may be provided a chassis extending in a longitudinaldirection for a tracked vehicle having an operator cabin, comprising: afirst portion directly under the operator cabin; and a second portionbehind the operator cabin in the longitudinal direction, the secondportion being lower to the ground than the first portion, the firstportion being reinforced so as to provide a greater resistance totorsion than the second portion.

Also, there may be provided a chassis for a tracked vehicle, comprising:an upper frame structure; and a lower frame structure; wherein the lowerframe structure spans a longitudinal distance along a direction oftravel of the vehicle; wherein over a first portion of the longitudinaldistance spanned by the lower frame structure, the lower frame structureoverlaps with a first section of the upper frame structure; wherein overa second portion of the longitudinal distance, the lower frame structureoverlaps with a second section of the upper frame structure, the secondsection of the upper frame structure comprising a torque box; andwherein the first and second sections of the upper frame structure aresecured to each other and to the lower frame structure.

There may also be provided a tracked vehicle comprising:

-   -   a chassis comprising an upper frame structure connected to a        lower frame structure, the lower frame structure spanning a        longitudinal distance along a longitudinal direction of the        tracked vehicle, wherein:        -   the lower frame structure includes a pair of parallel            elongated structural members extending along the            longitudinal distance, each of the structural members having            a top surface;        -   over a first portion of the longitudinal distance, the lower            frame structure is overlapped by the upper frame structure;            and        -   over at least a second portion of the longitudinal distance,            the lower frame structure is not overlapped by the upper            frame structure;    -   an operator cabin mounted to the upper frame structure;    -   a power plant mounted to the upper frame structure and        comprising a prime mover; and    -   a plurality of track assemblies for traction of the tracked        vehicle, a first one of the track assemblies being on a first        lateral side of the tracked vehicle, a second one of the track        assemblies being on a second lateral side of the tracked        vehicle, each track assembly of the plurality of track        assemblies being mounted to the lower frame structure and        comprising:        -   a plurality of wheels including:        -   a drive wheel;        -   an end wheel spaced apart from the drive wheel in the            longitudinal direction of the tracked vehicle; and        -   a plurality of support wheels arranged between the drive            wheel and the end wheel; and        -   an endless track disposed around the plurality of wheels,            the drive wheel being in driving engagement with the endless            track to impart motion to the endless track, wherein the            endless track has an inner surface and an outer surface,            wherein at any given time a portion of the endless track is            located directly above the support wheels, and wherein the            outer surface of said portion of the endless track is            further from the ground than the top surface of each of the            structural members.

There may also be provided a tracked vehicle comprising:

-   -   a chassis comprising a pair of parallel rails extending in a        longitudinal direction of the tracked vehicle;    -   an operator cabin mounted to the chassis;    -   a power plant mounted to a portion of the chassis above the        rails, and comprising a prime mover; and    -   a plurality of track assemblies for traction of the tracked        vehicle, a first one of the track assemblies being on a first        lateral side of the tracked vehicle, a second one of the track        assemblies being on a second lateral side of the tracked        vehicle, each track assembly of the plurality of track        assemblies being mounted to the chassis and comprising:        -   i) a plurality of wheels including:            -   a drive wheel;            -   an end wheel spaced apart from the drive wheel in the                longitudinal direction of the tracked vehicle; and            -   a plurality of support wheels arranged between the drive                wheel and the end wheel; and        -   ii) an endless track disposed around the plurality of wheels            for engaging ground on which the tracked vehicle travels,            the drive wheel being in driving engagement with the endless            track to impart motion to the endless track, wherein the            endless track comprises a top run extending between the            drive wheel and the end wheel over the support wheels,            wherein each rail of the pair of parallel rails has a top            surface, the top surfaces of the rails defining a plane, and            wherein the top run is further from the ground than the            plane.

There may also be provided a tracked vehicle comprising:

-   -   a chassis comprising an upper frame structure connected to a        lower frame structure, the lower frame structure including a        pair of parallel elongated structural members spanning a        longitudinal distance between a front end and a rear end of the        tracked vehicle, wherein:        -   over a first portion of the longitudinal distance, the            structural members are overlapped by the upper frame            structure;        -   over a second portion of the longitudinal distance that is            closer to the front end of the tracked vehicle than the            first portion, the elongated structural members are not            overlapped by the upper frame structure; and        -   over a third portion of the longitudinal distance that is            closer to the rear end of the tracked vehicle than the first            portion, the structural members are also not overlapped by            the upper frame structure;    -   an operator cabin mounted to the upper frame structure;    -   a power plant mounted to the upper frame structure and        comprising a prime mover; and    -   a pair of track assemblies for traction of the tracked vehicle,        a first one of the track assemblies being on a first lateral        side of the tracked vehicle, a second one of the track        assemblies being on a second lateral side of the tracked        vehicle, each of the track assemblies being mounted to a        respective one of the structural members and comprising:        -   a plurality of wheels including a drive wheel, an end wheel            and a plurality of support wheels arranged in-line between            the drive wheel and the end wheel; and        -   an endless track disposed around the plurality of wheels;    -   wherein each of the structural members has a top surface that is        at a lower elevation with respect to the ground than each drive        wheel's most elevated point.

These and other aspects of the invention will now become apparent tothose of ordinary skill in the art upon review of the followingdescription of embodiments of the invention in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of embodiments of the invention is providedbelow, by way of example only, with reference to the accompanyingdrawings, in which:

FIG. 1 shows a perspective view of an example of a tracked vehicleequipped with work equipment in accordance with an embodiment of theinvention;

FIG. 2 shows a top view of the tracked vehicle equipped with workequipment;

FIGS. 3 and 4 respectively show a side and a front view of the trackedvehicle without an equipment-mounting platform, such as a torque box,for mounting work equipment;

FIGS. 5 and 6 respectively show top and bottom perspective views of achassis of the tracked vehicle;

FIGS. 7 and 8 respectively show a top and a side view of the chassis;

FIG. 9 shows a perspective view of the chassis with an operator cabinand a power plant of the tracked vehicle mounted to an upper framestructure of the chassis;

FIG. 10 shows a perspective view of the chassis with the operator cabin,the power plant and the torque box mounted to a lower frame structure ofthe chassis;

FIG. 11 shows a cross-sectional view of a beam of the upper framestructure of the chassis taken along line 11-11 in FIG. 6;

FIG. 12 shows a front view of an example of a lateral plate of theplurality of lateral plates of the lower frame structure of the chassis;

FIG. 13 shows a cross-sectional view of the lateral plate taken alongline 13-13 in FIG. 12;

FIGS. 14 and 15 respectively show a top and a front view of a rearlateral plate of the lower frame structure;

FIG. 16 shows a top view of the chassis including a channel defined bythe lateral plates of the lower frame structure for receiving the torquebox;

FIGS. 17 and 18 respectively show a top view and a side view of thetorque box;

FIG. 19 shows a top view of the torque box in an embodiment wherespacers are used to mount the torque box to the lateral plates of thelower frame structure;

FIG. 20 shows a side view of the chassis with the torque box mounted toits lower frame structure and a stabilizer leg support assembly mountedto the upper frame structure frontwardly of the operator cabin;

FIG. 21 shows a perspective view of an example of longitudinal ends ofrail sections that are joined to form rails of the lower framestructure;

FIG. 22 shows a cross-section of the lower frame structure where a jointmember is used to join the rail sections to form the rails;

FIG. 23 shows an example of an attachment device used to secure the workequipment to the torque box;

FIG. 24 shows a perspective view of the power plant of the trackedvehicle;

FIG. 25 shows another perspective view of the power plant of the trackedvehicle with panels of a housing of the power plant removed;

FIG. 26 shows a side view of a track assembly of the vehicle mounted tothe lower frame structure of the chassis;

FIGS. 27 and 28 show a top view of an inner side, and a cross-sectionalview, of an endless track in accordance with an embodiment of theinvention;

FIGS. 29 and 30 show a perspective view of a ground-engaging outer side,and a perspective view of an inner side, of an endless track inaccordance with another embodiment of the invention;

FIG. 31 shows a perspective view of a support wheel of a track assemblyin accordance with another embodiment of the invention;

FIGS. 32 and 33 show a perspective view and a cross-sectional view of atrack tensioner in relation to wheels of a track assembly;

FIGS. 34 and 35 show track tensioners of the track assemblieshydraulically connected to a hydraulic drive system of the trackedvehicle;

FIG. 36 shows an operator cabin of the tracked vehicle configured in aone-person configuration;

FIG. 37 shows components of a user interface of the operator cabinconnected to other components of the tracked vehicle;

FIG. 38 shows a rear view of the lower frame structure and the trackassemblies with a rear drawbar of the lower frame structure to revealthe rails of the lower frame structure;

FIG. 39 shows a side view of the chassis mounted with the torque box,the operator cabin and the power plant;

FIG. 40 shows an example of an embodiment where adjacent ones of therail sections of the rails of the lower frame structure are spaced apartfrom one another such that the rails are discontinuous rails;

FIG. 41 shows a top view of the chassis of the vehicle mounted withwheels of the track assemblies of the vehicle mounted thereto;

FIG. 42 shows a side of the chassis of the vehicle with an idler wheel,a drive wheel and bogies mounted thereto;

FIG. 43 shows a perspective view of the chassis in accordance with avariant, where the lateral plates are configured are not connecteddirectly to the torque box;

FIG. 44 shows a perspective view of the chassis in accordance with avariant in which the lateral plates are configured such that the torquebox is disposed substantially on the rails of the lower frame structureof the chassis;

FIGS. 45 and 46 show a top view and a side view of a lateral middleplate of the chassis of FIG. 44;

FIGS. 47 and 48 show a top view and a side view of a lateral frontalplate of the chassis of FIG. 44; and

FIG. 49 shows a connection between the torque box and the lateralfrontal plate of FIGS. 47 and 48.

In the drawings, embodiments of the invention are illustrated by way ofexample. It is to be expressly understood that the description anddrawings are only for the purpose of illustrating certain embodiments ofthe invention and are an aid for understanding. They are not intended tobe a definition of the limits of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

FIGS. 1 to 4 show an example of a tracked utility vehicle 10 inaccordance with an embodiment of the invention. The tracked utilityvehicle 10 is designed to carry and enable use of work equipment 41,which includes one or more work implements such as, for example, acrane, a ladder, an aerial device, an aerial work platform, a lift, adrill rig, a digger derrick, a material handler, a mulcher or othervegetation management apparatus, and/or any other industrial apparatus,on various terrains, including rugged terrain (e.g., with mud, steephills, swamps, rocks, mud, and/or snow). This type of vehicle cansometimes be referred to as a “tracked carrier” or “tracked equipmentcarrier” vehicle.

The tracked utility vehicle 10 has a length L_(v), a width W_(v), and aheight H_(v) (measured without taking into account the work equipment41). These dimensions may allow the vehicle 10 to have a large payloadcapacity while being able to be used on a public road infrastructure.For example, in some embodiments, the length L_(v) may be at least 5 m,such as between 5 m and 10 m, in some cases between 6 m and 9 m, and insome cases between 7 m and 8 m; the width W_(v) may be at least 2 m,such as between 2 m and 5 m, in some cases between 2.5 m and 4.5 m, andin some cases between 3 m and 4 m; and the height H_(v) may be no morethan 4 m, in some cases no more than 3.5 m, and in some cases no morethan 3 m. The length L_(v), width W_(v), and height H_(v) may take onvarious other values in other embodiments.

The tracked utility vehicle 10 has a payload capacity which can be quitelarge. For example, in some embodiments, the payload capacity of thevehicle 10 may be at least 10000 lbs (about 4536 kg), in some cases atleast 15000 lbs (about 6804 kg), in some cases at least 20000 lbs (about9072 kg), in some cases at least 30000 lbs (about 13608 kg), in somecases at least 40000 lbs (18144 kg), in some cases at least 46000 lbs(20865 kg) and in some cases even more than 46000 lbs (e.g., 50000 lbs).The payload capacity may take on various other values in otherembodiments.

In this embodiment, the tracked utility vehicle 10 comprises a chassis12, a power plant 14, a plurality of track assemblies 16 ₁, 16 ₂, and anoperator cabin 20. The vehicle 10 has a longitudinal axis 59 defining alongitudinal direction of the vehicle 10 (i.e., a direction generallyparallel to its longitudinal axis 59) and transversal directions (i.e.,directions transverse to its longitudinal axis 59), including awidthwise direction (i.e., a lateral direction generally perpendicularto its longitudinal axis 59). The vehicle 10 also has a height directionwhich is normal to both its longitudinal direction and its widthwisedirection.

As will be described in more detail later on, in some embodiments, thetracked utility vehicle 10 may be configured to allow the work equipment41 to be mounted on the chassis 12 at a lowered position such as toallow a greater clearance between the work equipment 41 and the vehicleheight limit of the public road infrastructure and/or to allow tallerwork equipment 41 to be installed without surpassing the vehicle heightlimit of the public road infrastructure. In one non-limiting embodiment,a “lowered” position may refer to a position that is lower than a floorof an operator cabin of the vehicle, but the lowered position may alsobe defined in other ways and relative to other aspects of the trackedvehicle, as will be described herein below.

a) Chassis

The chassis 12 extends along the longitudinal axis 59 of the trackedutility vehicle 10 and has a length L_(c) measured between oppositelongitudinal ends of the chassis 12. The chassis 12 supports variouscomponents of the vehicle 10, including the power plant 14, the trackassemblies 16 ₁, 16 ₂, and the operator cabin 20. The chassis 12 alsosupports the work equipment 41 carried by the vehicle 10.

As further discussed below, in this embodiment, the chassis 12 isconfigured such as to receive an equipment-mounting platform 102, suchas a torque box for example, onto which can be mounted the workequipment 41. The equipment-mounting platform 102 may be similar incertain aspects to torque boxes used in trucks to transport workequipment. For instance, a manner in which the equipment-mountingplatform 102 is mounted to the chassis 12 may be akin to a manner inwhich torque boxes are installed on truck frames. As a result, workequipment such as the work equipment 41 may be as easily installable onthe tracked utility vehicle 10 as on trucks. Work equipment such as thework equipment 41 which may be primarily designed for trucks due to apotentially larger market for trucks can therefore also be easilyinstalled on the tracked utility vehicle 10.

In addition, in this embodiment, the chassis 12 is configured to receivethe equipment-mounting platform 102 at a lowered height portion of thechassis 12 such as to reduce an overall height H_(v-o) of the vehicle 10(i.e., a height including the work equipment 41) and/or to allow tallerwork equipment to be transported without exceeding vehicle heightlimits. The overall height H_(v-o) of the vehicle 10, measured with thework equipment 41 in a retracted nonworking state, may thus be designedtaking into account the vehicle height limit and a height of a traileron which the vehicle 10 may be transported on the public roadinfrastructure. For example, if a trailer having a height of 24 inchesis expected to be used for transporting the vehicle 10, the overallheight H_(v-o) of the vehicle 10 may be no more than 11.5 feet (3.5 m)if the vehicle height limit is 13.5 feet or no more than 12 feet (3.7 m)if the vehicle height limit is 14 feet. As another example, if a trailerhaving a height of 18 inches is expected to be used for transporting thevehicle 10, the overall height H_(v-o), of the vehicle 10 may be no morethan 12 feet if the vehicle height limit is 13.5 feet or no more than12.5 feet if the vehicle height limit is 14 feet. Thus, in variousexamples, the overall height H_(v-o) of the vehicle 10 may be no morethan 12.5 feet, in some cases no more than 12 feet, and in some cases nomore than 11.5 feet.

With additional reference to FIGS. 5 to 10, in this embodiment, thechassis 12 comprises an upper frame structure 60 and a lower framestructure 62, the upper and lower frame structures 60, 62 beingconnected to one another.

The upper frame structure 60 is that portion of the chassis 12 on whichrests and to which are secured the operator cabin 20 and the power plant14. For its part, the lower frame structure 62 is that portion of thechassis 12 to which is secured the equipment-mounting platform 102 ontowhich the work equipment 41 is mounted.

In this embodiment, the upper frame structure 60 comprises a pair ofbeams 64 ₁, 64 ₂ extending in the longitudinal direction of the vehicle10 and spaced apart in the widthwise direction of the vehicle 10. Inthis embodiment, the upper frame structure 60 also comprises first andsecond crossmembers 66 ₁, 66 ₂ extending transversally to the beams 64₁, 64 ₂ and thus transversally to the longitudinal direction of thevehicle 10.

In this embodiment, each beam 64 _(i) is a hollow beam (i.e., a beamdefining a hollow interior) and more specifically a rectangular boxbeam. As shown in FIG. 11, the beam 64 _(i) comprises a top surface 65,a bottom surface 67 opposite the top surface 65, and a pair of lateralsurfaces 68 ₁, 68 ₂ opposite one another. The beam 64 _(i) is made ofmetallic material, in this case steel. Moreover, each beam 64 _(i) isdimensioned such that the beams 64 ₁, 64 ₂ are able to support theoperator cabin 20 and the power plant 14. For example, in some examplesof implementation, the beam 64 _(i) may have a height H_(B) measuredbetween its top and bottom surfaces 65, 67 of at least 8 inches, in somecases at least 10 inches, in some cases at least 12 inches, and in somecases at least 16 inches. In some examples of implementation, the beam64 _(i) may have a width W_(B) measured between its lateral surfaces 68₁, 68 ₂ of at least 4 inches, in some cases at least 8 inches, and insome cases at least 12 inches. Moreover, in some examples ofimplementation, the beam 64 _(i) may have a wall thickness T_(W) of atleast ¼ inches, in some cases at least ⅝ inches, and in some cases atleast ¾ inch. In this example, the beam 64 _(i) can be made by formingdifferent sections of steel plates and subsequently welding themtogether, although other processes are possible such as an extrusionprocess or any other suitable process. Dimensions of the beams 64 ₁, 64₂ may take on various other values in other embodiments.

The beams 64 ₁, 64 ₂ may be configured in various other ways in otherembodiments. For instance, in some embodiments, each one of the beams 64₁, 64 ₂ may have a cross-sectional shape other than rectangular (e.g.,circular or otherwise curved, square, etc.). In some examples, the beams64 ₁, 64 ₂ may be C-beams, I-beams, or any other suitable elongatedstructural member. As another example, in some embodiments, the beams 64₁, 64 ₂ may be made of material other than steel.

Furthermore, in some embodiments, the beams 64 ₁, 64 ₂ may be joined viaa plate fastened to the top surface 65 of each beam 64 _(i) and anotherplate fastened to the bottom surface 67 of each beam 64 _(i). Forinstance, such plates may be steel plates that are welded to the beams64 ₁, 64 ₂ or fastened in any other suitable way to the beams 64 ₁, 64₂. In such embodiments, the beams 64 ₁, 64 ₂ along with the steel platesfastened thereto may form a hollow structure having a cross-sectionalspan greater than the combined cross-sectional spans of each of thebeams 64 ₁, 64 ₂. This may be useful to reinforce the beams 64 ₁, 64 ₂such that they have a greater stiffness to resist applied torques.

The crossmembers 66 ₁, 66 ₂ are secured to the beams 64 ₁, 64 ₂ tointerconnect the beams 64 ₁, 64 ₂. More particularly, in thisembodiment, the crossmembers 66 ₁, 66 ₂ are secured to the beams 64 ₁,64 ₂ via fasteners (e.g., bolts and/or rivets). The crossmembers 66 ₁,66 ₂ may be secured to the beams 64 ₁, 64 ₂ in other ways in otherembodiments (e.g., by welding). Each crossmember 66 _(i) is an elongatedand hollow structural member including a top surface 74 ₁, a bottomsurface 74 ₂, and opposite lateral surfaces 74 ₃, 74 ₄. The lateralsurfaces 74 ₃, 74 ₄ comprise recesses 69 configured for positioning thecrossmember 66 _(i) onto the beams 64 ₁, 64 ₂. The crossmember 66 _(i)is made of metallic material, in this case steel.

In this embodiment, the first crossmember 66 ₁ has a length greater thana length of the second crossmember 66 ₂. Moreover, in this embodiment,the first crossmember 66 ₁ is connected to the beams 64 ₁, 64 ₂ suchthat it extends beyond a widthwise span of the beams 64 ₁, 64 ₂ (i.e., aspan between outboard lateral walls of the beams 64 ₁, 64 ₂ in thewidthwise direction of the vehicle 10) on both sides of the widthwisespan of the beams 64 ₁, 64 ₂. In this example, the second crossmember 66₂ is connected to the beams 64 ₁, 64 ₂ such that the second crossmember66 ₂ extends beyond the widthwise span of the beams 64 ₁, 64 ₂ on asingle side of the widthwise span of the beams 64 ₁, 64 ₂. In thisembodiment, the second crossmember 66 ₂ has a height greater than thefirst crossmember 66 ₁ such that a distance between the top surface 74 ₁of the second crossmember 66 ₂ and the top surface 65 of the beams 64 ₁,64 ₂ is greater than a distance between the top surface 74 ₁ of thefirst crossmember 66 ₁ and the top surface 65 of the beams 64 ₁, 64 ₂.

The crossmembers 66 ₁, 66 ₂ may be any other suitable elongatedstructural member in other embodiments. As another example, in someembodiments, the crossmembers 66 ₁, 66 ₂ may be made of material otherthan steel.

The lower frame structure 62 provides a main structure for supportingthe track assemblies 16 ₁, 16 ₂ and the equipment-mounting platform 102onto which the work equipment 41 is mounted. In this embodiment, thelower frame structure 62 comprises a pair of parallel rails 80 ₁, 80 ₂extending along the longitudinal direction of the vehicle 10 and spacedapart in the widthwise direction of the vehicle 10. More specifically,the lower frame structure 62 is generally centered in relation to thelongitudinal axis 59 of the vehicle 10 such that the longitudinal axis59 bisects a width of the lower frame structure 62. The lower framestructure 62 also comprises a plurality of crossmembers 82 ₁-82 ₃extending transversally to the longitudinal direction of the vehicle 10between the rails 80 ₁, 80 ₂. The lower frame structure 62 alsocomprises a front drawbar 87 ₁ and a rear drawbar 87 ₂. The lower framestructure 62 has a length L_(LF) defined between its oppositelongitudinal ends 91 ₁, 91 ₂.

Although the rails 80 ₁, 80 ₂ of the lower frame structure 62 and thebeams 64 ₁, 64 ₂ of the upper frame structure 60 are respectivelydescribed as “rails” and “beams”, this is merely done to avoid confusionwhen referring to them. In some embodiments, the rails 80 ₁, 80 ₂ andthe beams 64 ₁, 64 ₂ may be similarly structured, while in others theymay be quite different. For instance, in this embodiment, each of therails 80 ₁, 80 ₂ is a rectangular box beam similar to the beams 64 ₁, 64₂. Each rail 80 _(i) comprises a top surface 93, a bottom surface 94opposite the top surface 93, and a pair of lateral surfaces 97 ₁, 97 ₂opposite one another. The rails 80 ₁, 80 ₂ are made of metallicmaterial, in this case steel. The rails 80 ₁, 80 ₂ may be configured invarious other ways in other embodiments. For example, in someembodiments, each of the rails 80 ₁, 80 ₂ may be a hollow beam having across-sectional shape other than rectangular (e.g., circular orotherwise curved). In other examples, each of the rails 80 ₁, 80 ₂ couldbe implemented as a non-hollow beam, such as a C-beam or an I-beam (orH-beam), or any other suitable elongated structural member. As anotherexample, in some embodiments, the rails 80 ₁, 80 ₂ may be made ofmaterial other than steel.

Each rail 80 _(i) is dimensioned such that the rails 80 ₁, 80 ₂ are ableto support the equipment-mounting platform 102 and the work equipment41. For example, in this embodiment, the rail 80 _(i) may havedimensions similar to those of the beams 64 ₁, 64 ₂ and may bemanufactured in a similar manner. In this example, the rail 80 _(i) canbe made by forming different sections of steel plates and subsequentlywelding them together, although other processes are possible such as anextrusion process or any other suitable process. Dimensions of the rails80 ₁, 80 ₂ may take on various other values in other embodiments.

In this embodiment, the rails 80 ₁, 80 ₂ of the lower frame structure 62are aligned with the beams 64 ₁, 64 ₂ of the upper frame structure 60 inthe widthwise direction of the vehicle 10. More specifically, in thisembodiment, a position of each of the rails 80 ₁, 80 ₂ in the widthwisedirection of the vehicle 10 corresponds to a position of each of thebeams 64 ₁, 64 ₂ in the widthwise direction of the vehicle 10. Forexample, the rail 80 ₁ is positioned such that its outboard lateral wall97 ₁ is coplanar with the outboard lateral wall 68 ₁ of the beam 64 ₁.Moreover, in this embodiment, the rails 80 ₁, 80 ₂ and the beams 64 ₁,64 ₂ have a same width (i.e., a distance between their respectivelateral walls) and thus the inboard lateral wall 97 ₂ of the rail 80 ₁is also coplanar with the inner lateral wall 68 ₂ of the beam 64 ₁. Inother embodiments, the rails 80 ₁, 80 ₂ and the beams 64 ₁, 64 ₂ may notbe aligned with one another. For example, the rails 80 ₁, 80 ₂ and thebeams 64 ₁, 64 ₂ may be offset relative to one another in the widthwisedirection of the vehicle 10.

The crossmembers 82 ₁-82 ₃ of the lower frame structure 62 are securedto the rails 80 ₁, 80 ₂ and are configured to support an electricharness and hydraulic hoses of the tracked utility vehicle 10. In thisembodiment, the crossmembers 82 ₁-82 ₃ comprise elongated L-beams. Thecrossmembers 82 ₁-82 ₃ may be any other suitable type of beams in otherembodiments. Moreover, in this embodiment, the crossmembers 82 ₁-82 ₃are welded to the rails 80 ₁, 80 ₂. The crossmembers 82 ₁-82 ₃ may besecured to the rails 80 ₁, 80 ₂ in other ways in other embodiments(e.g., by fasteners such as bolts and/or rivets). Although in thisembodiment only three crossmembers are depicted, more or lesscrossmembers may be included in other embodiments.

The lower frame structure 62 also comprises a plurality of supportmembers 104 ₁-104 ₃ that extend transversally to the longitudinaldirection of the vehicle 10. These support members 104 ₁-104 ₃ areconfigured to stiffen the chassis 12 by providing support in its lateraldirection and to receive respective wheel mounting structures of thetrack assemblies 16 ₁, 16 ₂. More specifically, the support members 104₁, 104 ₂ extend between the rails 80 ₁, 80 ₂ and are connected thereto(e.g., via welding) while the support member 104 ₃ extends at aconnection between the upper and lower frame structures 60, 62. In thisembodiment, the support members 104 ₁-104 ₃ comprise a hollowcylindrical body.

In this embodiment, each rail 80 _(i) comprises a plurality of separaterail sections 35 ₁-35 _(S) that are joined to form the rail 80 _(i).Adjacent ones of the rail sections 35 ₁-35 _(S) are joined at locationswhere the support members 104 ₁, 104 ₂ extend between the rails 80 ₁, 80₂. To that end, as shown in FIG. 21, the rail sections 35 ₁-35 _(S) aresimilarly structured, each rail section 35 _(i) being elongated andcomprising an aperture 55 at one of its longitudinal ends (or at bothlongitudinal ends in the case of the rail section positioned between thesupport members 104 ₁, 104 ₂). The aperture 55 is configured to fit ashape and size of a support member 104 _(i). To that end, in thisexample, the aperture 55 is in the shape of a semi-circle such thatadjacent ones of the rail sections 35 ₁-35 _(S) together form a circularopening to fit a support member 104 _(i). The rail sections 35 ₁-35 _(S)may be joined in any suitable way. For instance, adjacent rail sections35 ₁-35 _(S) may be welded together to form the rail 80 _(i).Additionally or alternatively, as shown in FIG. 22, the rail sections 35₁-35 _(S) may be joined via joint members 81 _(i)-81 _(R) configured tojoin adjacent ones of the rail sections 35 ₁-35 _(S) to form the rail 80_(i). Each joint member 81 _(i) comprises an opening for fitting arespective support member 104 _(i) and is positioned to contact adjacentones of the rail section 35 ₁-35 _(S) at a portion of their topsurfaces, bottom surfaces, and inboard lateral surfaces (correspondingto the top surface 93, the bottom surface 94 and an inboard one of thelateral surfaces 97 ₁, 97 ₂ of the rails 80 ₁, 80 ₂).

In some embodiments, as shown in FIG. 40, the rail sections 35 ₁-35 _(S)of each rail 80 _(i) may be arranged such that they do not form acontinuous rail 80 _(i). In other words, the rail 80 _(i) may be a“discontinuous” rail in that its rail sections 35 ₁-35 _(S) do notcontact one another. In such embodiments, the rail sections 35 ₁-35 _(S)do not comprise an aperture and adjacent ones of the rail sections 35₁-35 _(S) are spaced apart by a distance equal to or greater than adiameter of the support member 104 _(i). A joint member 81 _(i) is thenfastened to (e.g., welded to) each of the adjacent rail sections(denoted as 35 _(i), 35 _(j) in FIG. 40) to form a “bridge” (i.e., aconnection) between each one of the adjacent rail sections 35 ₁-35 _(S).

The lower frame structure 62 also comprises a plurality of side wallsfor positioning and attaching the equipment-mounting platform 102 to thelower frame structure 62. The side walls may be made of lateral plates106 ₁-106 ₆. As shown in FIGS. 12 and 13, each lateral plate 106 _(i)comprises an interior surface 107 facing a center of the vehicle 10 inthe widthwise direction of the vehicle 10 and an exterior surface 108opposite the interior surface 107. The interior and exterior surfaces107, 108 of the lateral plate 106 _(i) are substantially flat. Eachlateral plate 106 _(i) is secured to a respective one of the rails 80 ₁,80 ₂ such that the interior and exterior surfaces 107, 108 of thelateral plate 106; are parallel to the longitudinal direction of thevehicle 10. More particularly, a lower portion 110 of the lateral plate106 _(i) is fastened to a respective one of the rails 80 ₁, 80 ₂ whilean upper portion 111 of the lateral plate 106 _(i) is configured to befastened to the equipment-mounting platform 102. To that end, thelateral plate 106 _(i) is positioned such that its upper portion 111extends beyond the top surface 93 of the rail 80 _(i) to which thelateral plate 106 _(i) is mounted.

In this embodiment, the upper portion 111 of the lateral plate 106 _(i)has a generally rectangular shape and comprises a plurality of holes 109₁-109 _(H) for inserting a fastening element configured to engage theequipment-mounting platform 102. The lateral plates 106 ₁-106 ₆ may beconfigured similarly to “fishplates” typically found on truck frames andused to attach a torque box thereto. Therefore, the lateral plates 106₁-106 ₆ may be familiar to a person accustomed to using fishplates ontruck frames. This may thus facilitate the installation of theequipment-mounting platform 102 onto the lower frame structure 62.

In this embodiment, some of the lateral plates 106 ₁-106 ₆ arepositioned such that they are aligned with respective ones of thesupport members 104 ₁-104 ₃ in the longitudinal direction of the vehicle10. For example, the lateral plates 106 ₂, 106 ₅ are aligned with thesupport member 104 ₁ in the longitudinal direction of the vehicle 10.Each of these lateral plates may comprise an opening 113 in its lowerportion 110 that is shaped and dimensioned to fit the support member 104_(i) with which it is aligned such as to enable the inner surface 107 ofthe lateral plate 106 _(i) to be placed in contact with a respective oneof the rails 80 ₁, 80 ₂. In some cases, the lower portion 110 of thelateral plate 106 _(i) may be fastened to a respective one of thesupport members 104 ₁-104 ₃.

While in this embodiment the lateral plates 106 ₁-106 ₆ are welded tothe rails 80 ₁, 80 ₂, the lateral plates 106 ₁-106 ₆ may be fastened tothe rails 80 ₁, 80 ₂ in any other suitable way in other embodiments(e.g., via bolts and/or rivets). Moreover, in some embodiments, thelateral plates 106 ₁-106 ₆ may be made integrally with the rails 80 ₁,80 ₂. That is, the lateral plates 106 ₁-106 ₆ may be manufacturedtogether with the rails 80 ₁, 80 ₂ such that they constitute a singlecomponent.

In embodiments where adjacent ones of the rail sections 35 ₁-35 _(S) ofthe rails 80 ₁, 80 ₂ are spaced apart from one another such that eachone of the rails 80 ₁, 80 ₂ is a discontinuous rail, as shown in FIG.40, a lateral plate 106 _(i) is fastened to each of the adjacent railsections 35 _(i), 35 _(j) to connect, along with the joint member 81_(i), the adjacent rail sections 35 _(i), 35 _(j) to one another.

Each lateral plate 106 _(i) may be dimensioned such as to support theequipment-mounting platform 102. For instance, in some examples ofimplementation, the lateral plate 106 _(i) may have a thickness T_(P) ofat least ⅜ inch, in some cases at least, ½ inch, in some cases at least⅝ inch, and in some cases at least 1 inch.

In this embodiment, the plurality of lateral plates 106 ₁-106 ₆ includesa pair of frontal plates 106 ₃, 106 ₆, a pair of middle plates 106 ₂,106 ₅, and a pair of rear plates 106 ₁, 106 ₄. Besides being connectedto the rails 80 ₁, 80 ₂ of the lower frame structure 62, the frontalplates 106 ₃, 106 ₆ are also connected to the upper frame structure 60.More specifically, each of the frontal plates 106 ₃, 106 ₆ is connectedto a respective one of the beams 64 ₁, 64 ₂ of the upper frame structure60. For example, the frontal plates 106 ₃, 106 ₆ may be welded to thebeams 64 ₁, 64 ₂ or otherwise connected to the beams 64 ₁, 64 ₂ (e.g.,via bolts and/or rivets).

Moreover, in this embodiment, the rear plates 106 ₁, 106 ₄ arepositioned such that they extend beyond the span of the rails 80 ₁, 80 ₂in the longitudinal direction of the vehicle 10. As such, in thisembodiment, the rear plates 106 ₁, 106 ₄ define the longitudinal end 91₂ of the lower frame structure 62 (i.e., a rearmost endpoint of thelower frame structure 62).

In this embodiment, the rear plates 106 ₁, 106 ₄ are structureddifferently than the remainder of the lateral plates in that they do notcomprise an opening for fitting a support member 104 _(i) since they arenot aligned with any of the support members 104 ₁-104 ₃. Rather, asshown in FIGS. 14 and 15, each of the rear plates 106 ₁, 106 ₄ comprisesa plate portion 115 configured similarly to the frontal plates 106 ₃,106 ₆ and the middle plates 106 ₂, 106 ₅, and a drive wheel supportstructure 117 for supporting a drive wheel of a respective one of thetrack assemblies 16 ₁, 16 ₂. The drive wheel support structure 117comprises a cylindrical body 119 protruding from the outer surface 108of the plate portion 115 and terminating in a flange 121. The flange 121comprises a plurality of openings 127 ₁-127 _(n) for mounting aplanetary gearbox (not shown) configured to drive the drive wheel ofeach track assembly 16 ₁, 16 ₂. The cylindrical body 119 defines anopening 123 in which an axle of a respective one of the drive wheels ofthe track assemblies 16 ₁, 16 ₂ may be disposed. The drive wheel supportstructure 117 further comprises a pair of webs 125 ₁, 125 ₂ attached tothe plate portion 115 and to the cylindrical body 119 in order tosupport the cylindrical body 119 of the drive wheel support structure117.

While in this embodiment the plurality of lateral plates 106 ₁-106 ₆includes six lateral plates, the plurality of lateral plates may includeany other suitable number of lateral plates. More specifically, theplurality of lateral plates includes at least two lateral plates. Forexample, in some embodiments, the side walls may include only twoopposing lateral plates, each lateral plate spanning a majority of thelength of the lower frame structure 62.

The positioning of the lateral plates 106 ₁-106 ₆ may facilitate theinstallation of the equipment-mounting platform 102 onto the lower framestructure 62. More specifically, as shown in FIG. 16, the lateral plates106 ₁-106 ₆ are secured to the rails 80 ₁, 80 ₂ such that some of thelateral plates 106 ₁-106 ₆ are separated in the widthwise direction ofthe vehicle 10 to define a channel 162 for laterally bounding theequipment-mounting platform 102. A width W_(C) of the channel 162defined between the side walls/lateral plates 106 ₁-106 ₆ may take onvarious values. The channel 162 is also longitudinally bound at one endby a transversal connection plate 174 which is configured to connect theupper frame structure 60 to the lower frame structure 62 and will bedescribed in more detail later.

In a non-limiting embodiment, the width W_(C) of the channel 162 maycorrespond to a “nominal truck frame side rail spacing”. The nominaltruck frame side rail spacing may be different for differentjurisdictions. The nominal truck frame side rail spacing may be 34inches (about 0.86 m) in the United States, and 700 mm (about 27.5inches) in Europe and in Japan). Accordingly, the width W_(C) of thechannel 162 may thus be 34 inches, or 700 mm, in various embodiments,depending on the jurisdiction. For a given jurisdiction, one way ofdefining the “nominal truck frame side rail spacing” is to refer to theaverage (mean, median or mode) an industry-standard advertised spacingof side rails of a frame of a truck chassis for across all trucks with agross vehicle weight rating (GVWR) over 14000 lbs (6351 kg) sold in thegiven jurisdiction during a given time frame. By “advertised” one maytake the spacing listed in the owner's manual or other specificationsheet. (A truck's GVWR corresponds to a curb weight of the truck plus acargo and passenger weight capacity of the truck. In the United States,a GVWR over 14000 lbs would be a class 4 or higher class according tothe U.S. Department of Transportation's truck classification.) Otherways of defining the nominal truck frame side rail spacing may be reliedupon.

In other non-limiting embodiments, the width W_(C) of the channel 162may be greater than the nominal truck frame side rail spacing, in orderto accommodate manufacturing tolerances and/or equipment variations. Forexample, in a particular jurisdiction, the width W_(C) of the channel162 may be between 0 and 3 inches greater than the nominal truck frameside rail spacing in that jurisdiction. Thus, by way of non-limitingexample, in countries where the nominal truck frame side rail spacing is34 inches, the width W_(C) of the channel 162 may be 35¼ inches, 36inches or 36 inches or 36 ½ inches.

In still other non-limiting embodiments, the width W_(C) of the channel162 may not bear a particular relationship to a nominal truck frame siderail spacing at all, but may be selected by the manufacturer accordingto other criteria. For example, the width W_(C) of the channel 162 mayhave any suitable value, such as 32 inches, 36 inches, 40 inches and thelike. In other embodiments, the width W_(C) of the channel 162 may bebetween 30 and 34 inches, between 32 inches and 34 inches, or evenbetween 33 inches and 34 inches. In still other embodiments, the W_(C)of the channel 162 may be less than 30 inches.

The lower frame structure 62 may be positioned such that a portion of alongitudinal distance along the longitudinal direction of the vehicle 10that is spanned by the lower frame structure 62 (i.e., its lengthL_(LF)) does not overlap (i.e., is non-overlapping with respect to) theupper frame structure 60. With additional reference to FIG. 8, in thisembodiment, the lower frame structure 62 is positioned such that itoverlaps with the upper frame structure 60 over a first portion P₁ ofits length L_(LF) and does not overlap with (i.e., is non-overlappingwith respect to) the upper frame structure 60 over a second portion P₂of its length L_(LF). It is also noted that the first portion P₁ of thelength L_(LF) of the lower frame structure 62 is located further towardsa front of the vehicle 10 than the second portion P₂ of the lengthL_(LF) of the lower frame structure 62.

In this embodiment, the second portion P₂ of the length L_(LF) of thelower frame structure 62 is longer than the first portion P₁ of thelength L_(LF) of the lower frame structure 62. That is, in thisembodiment, a longitudinal span of the lower frame structure 62 overwhich the upper and lower frame structures 60, 62 do not overlap isgreater than the longitudinal span of the lower frame structure 62 overwhich the upper and lower frame structures 60, 62 do overlap. Forinstance, in some cases, the second portion P₂ of the length L_(LF) ofthe lower frame structure 62 may be at least 10% longer than the firstportion P₁, in some cases at least 20% longer, in some cases at least30% longer, in some cases at least 40% longer and in some cases evengreater than 40% longer than the first portion P1 (e.g., 50%, 60% oreven 100% if not more).

In this manner, the second portion P₂ of the length L_(LF) of the lowerframe structure 62 may define a lowered platform-receiving area (e.g.,to receive the equipment-mounting platform 102) that would otherwise notbe available if the entire length L_(LF) of the lower frame structure 62overlapped the upper frame structure 60.

In this embodiment, the rails 80 ₁, 80 ₂ of the lower frame structure 62extend along at least the second portion P₂ of the length L_(LF) of thelower frame structure 62. Moreover, in this embodiment, the rails 80 ₁,80 ₂ also extend along the first portion P₁ of the length L_(LF) of thelower frame structure 62.

The equipment-mounting platform 102 is a platform that is positionedintermediate the work equipment 41 and the lower frame structure 62. Inthis embodiment, the equipment-mounting platform 102 is a torque box andwill thus be referred to as such. In this embodiment, as shown in FIGS.17 and 18, the torque box 102 is generally rectangular and comprises atop surface 164, a ground-facing bottom surface 166 opposite the topsurface 164, lateral surfaces 168 ₁, 168 ₂, and longitudinal endsurfaces 170 ₁, 170 ₂. In this embodiment, the torque box 102 comprisesequipment-mounting structures 182 protruding from the top surface 164 ofthe torque box 102 for mounting the work equipment 41 onto the torquebox 102. The torque box 102 has a width W_(TB) defined between itslateral surfaces 168 ₁, 168 ₂ and a height H_(TB) defined between itstop and bottom surfaces 164, 166.

In this embodiment, the torque box 102 further comprises a stabilizerleg support assembly 172 affixed to the torque box 102 at its rear endsuch that the stabilizer leg support assembly 172 defines the rearlongitudinal end surface 170 ₁ of the torque box 102. The stabilizer legsupport assembly 172 is configured to receive stabilizer legs (shown inFIG. 2) that may engage the ground for providing support to the workequipment 41 when it is deployed (i.e., in an extended state).

In this embodiment, the torque box 102 also comprises a front plate 178at its front end such that the front plate 178 defines the frontlongitudinal end surface 170 ₂ of the torque box 102. The front plate178 is configured to connect the torque box 102 to the transversalconnection plate 174.

The torque box 102 is mounted to the lower frame structure 62 via thelateral plates 106 ₁-106 ₆ of the lower frame structure 62. Morespecifically, the torque box 102 is configured to fit the channel 162defined by the lateral plates 106 ₁-106 ₆. To that end, in thisembodiment, the width W_(C) of the channel 162 is at least as large asthe width W_(TB) of the torque box 102. In other embodiments, the widthW_(C) of the channel 162 may be greater than the width W_(TB) of thetorque box 102. In such embodiments, as shown in FIG. 19, at least onespacer 180 may be provided between the torque box 102 and at least oneof the lateral plates 106 ₁-106 ₆ such as to securely fix the torque box102 within the channel 162.

The torque box 102 may be secured to the lateral plates 106 ₁-106 ₆ inany suitable manner. For instance, in this embodiment, the torque box102 is riveted to the lateral plates 106 ₁-106 ₆ via rivets extendingthrough the holes 109 ₁-109 _(H) of the lateral plates 106 ₁-106 ₆. Inother embodiments, the torque box 102 may be bolted or welded to thelateral plates 106 ₁-106 ₆. In yet other embodiments, the torque box 102may be welded and riveted and/or bolted to the lateral plates 106 ₁-106₆. In this embodiment, the torque box 102 is also secured to thetransversal connection plate 174 (e.g., via rivets).

In this embodiment, the torque box 102 is mounted above the rails 80 ₁,80 ₂. More specifically, in this embodiment, as shown in FIG. 20, whenthe torque box 102 is mounted to the lower frame structure 62, thebottom surface 166 of the torque box 102 is separated from the topsurface 93 of the rails 80 ₁, 80 ₂ by a vertical gap 176 (i.e., an emptyspace). Thus, in this embodiment, when the torque box 102 is mounted tothe lower frame structure 62, the torque box 102 does not rest on therails 80 ₁, 80 ₂. That is, the surfaces of the torque box 102 do notcontact the surfaces of the rails 80 ₁, 80 ₂. The vertical gap 176between the top surface 93 of the rails 80 ₁, 80 ₂ and the bottomsurface 166 of the torque box 102 may be useful for routing cablesand/or hoses related to the operation of the track assemblies 16 ₁, 16 ₂and/or the torque box 102. In other embodiments, for example whereheight constraints may be more severe, the torque box 102 may be mountedto the lower frame structure 62 such that the bottom surface 166 of thetorque box 102 rests on the rails 80 ₁, 80 ₂.

In embodiments where the torque box 102 is mounted to the lower framestructure 62 such that the bottom surface 166 of the torque box 102rests on the rails 80 ₁, 80 ₂, as shown in FIG. 23, the torque box 102may be alternatively or additionally secured to the lower framestructure 62, and more specifically to the rails 80 ₁, 80 ₂, by aplurality of attachment devices 92 ₁-92 _(R). For example, each of theattachment devices 92 ₁-92 _(R) includes an attachment threaded rodassembly. Each attachment threaded rod assembly 92 _(i) includes athreaded rod 95 and a bottom link 96 disposed around the rail 80 _(i).Although the attachment devices 92 ₁-92 _(R) securing the torque box 102to the rails 80 ₁, 80 ₂ are attachment threaded rod assemblies, variousother types of attachment devices may be used in other embodiments.

In this embodiment, the torque box 102 is mounted to the lower framestructure 62 such that the torque box 102 does not extend into the firstportion P₁ of the length L_(LF) of the lower frame structure 62. Thatis, in this embodiment, the torque box 102 extends solely along thesecond portion P₂ of the length L_(LF) of the lower frame structure 62.For example, the channel 162 defined by the lateral plates 106 ₁-106 ₆is longitudinally bound by the front attachment plate 174 and thus thetorque box 102 does not extend beyond the front attachment plate 174.

In this embodiment, the top surface 164 of the torque box 102 issubstantially flat over a majority of the second portion P₂ of thelength L_(LF) of the lower frame structure 62. In other words, a profileheight of the top surface 164 of the torque box 102 is largely—althoughnot necessarily entirely—constant along its longitudinal span. Forexample, the equipment-mounting structures 182 of the torque box 102 maydefine locations at which the profile height of the top surface 164 ofthe torque box 102 varies.

The stabilizer leg support assembly 172 of the torque box 102 receives apair of stabilizer legs (shown in FIG. 2) that are configured to supportthe vehicle 10 on the ground when the work equipment 41 is deployed(i.e., extended and ready to use). In this embodiment, the stabilizerleg support assembly 172 is a first stabilizer leg support assembly 172,the torque box 102 working in conjunction with a second stabilizer legsupport assembly 184 that is separate from (i.e., not directlyphysically connected to) the torque box 102. The second stabilizer legsupport assembly 184 is configured to receive another pair of stabilizerlegs for supporting the vehicle 10 on the ground. The second stabilizerleg support assembly 184 is positioned at a front portion of the vehicle10. More specifically, the second stabilizer leg support assembly 184 isconnected to the beams 64 ₁, 64 ₂ of the upper frame structure 60 at aposition frontwardly of the operator cabin 20.

The lower frame structure 62 is generally disposed at a lower height offthe ground than the upper frame structure 60 in order to receive thetorque box 102 at a lower height off the ground than if the torque box102 were secured to the upper frame structure 60.

For instance, in this embodiment, the top surface 93 of each rail 80_(i) of the pair of parallel rails 80 ₁, 80 ₂ is closer to the groundthan the top surface of the pair of parallel beams 64 ₁, 64 ₂ of theupper frame structure 60. For instance, in some cases, a verticaldistance between the top surface 93 of a rail 80 _(i) of the lower framestructure 62 and the top surface of a beam 64 _(i) of the upper framestructure 60 is at least 8 inches, in some cases at least 12 inches, insome cases at least 16 inches and in some cases even greater than 16inches (e.g., 20 inches).

The upper and lower frame structures 60, 62 of the chassis 12 areconnected at the first portion P₁ of the length L_(LF) of the lowerframe structure 62 (i.e., at the portion over which they overlap). Morespecifically, at the first portion P₁ of the length L_(LF) of the lowerframe structure 62, the rails 80 ₁, 80 ₂ of the lower frame structure 62are located directly under the beams 64 ₁, 64 ₂ of the upper framestructure 60 and are connected thereto.

Connectedness of the upper and lower frame structures 60, 62 providesthe chassis 12 with a greater resistance to torsion along the firstportion P₁ than along the second portion P₂ of the length L_(LF) of thelower frame structure 62. More specifically, the connectedness of theupper and lower frame structures 60, 62 reinforces the portion of thechassis 12 (including the upper and lower frame structures 60, 62) underthe operator cabin to provide a greater resistance to torsion. Forexample, due to this reinforcement, the portion of the chassis 12 underthe operator cabin 20 (i.e., the reinforced portion of the chassis 12)may have a greater resistance to torsion than a portion of the chassis12 behind the operator cabin 20. For instance, in this embodiment, whena torque is applied to the chassis 12 about the longitudinal axis 59 ofthe vehicle 10, a von Mises stress generated at a point located halfwayalong a longitudinal span of the first portion P₁ of the length L_(LF)of the lower frame structure 62 is smaller than a von Mises stressgenerated at a point located halfway along a longitudinal span of thesecond portion P₂ of the length L_(LF) of the lower frame structure 62.

Furthermore, the connectedness of the upper and lower frame structures60, 62 reinforces the chassis 12 such that the reinforced portion of thechassis 12 has a greater rigidity than other portions of the chassis 12.For instance, a point located halfway along the longitudinal portion P₁of the length L_(LF) of the lower frame structure 62 may be displaced bya smaller distance than a point located halfway along the longitudinalportion P₂ of the length L_(LF) of the lower frame structure 62 inresponse to an applied forced thereat. This increased rigidity of thereinforced portion of the chassis 12 may prevent excessive displacementof work implements positioned on a side of the vehicle 10. For example,when the work equipment 41 includes a crane, the increased rigidity ofthe reinforced portion of the chassis 12 may prevent the crane frombeing excessively displaced in response to a torque about thelongitudinal axis 59 of the vehicle 10 when the crane is positioned on aside of the vehicle 10.

As such, when the work equipment 41 is attached to the torque box 102which is mounted to the lower frame structure 62, the reinforced portionof the chassis 12 described above, due to its increased rigidity, willtransmit forces caused by operation of the work equipment 41 to thestabilizer legs supported by the second stabilizer leg support assembly184 at the front of the vehicle 10. By transmitting forces to the frontstabilizer legs, the reinforced portion of the chassis 12 may avoidoverloading the rear stabilizer legs of the vehicle 10, thus preventingexcessively elevated stresses from being generated at the rearstabilizer legs.

In this embodiment, the upper frame structure 60 is connected to thelower frame structure 62 by a connection structure 185 which comprisesthe transversal connection plate 174, the lateral plates 106 ₃, 106 ₆, apair of front connection plates 186 ₁, 186 ₂ and a pair of reinforcementarm assemblies 195 ₁, 195 ₂. The transversal connection plate 174extends transversally to the longitudinal direction of the vehicle 10and is fastened to rear longitudinal ends of each of the beams 64 ₁, 64₂ and to at least the top surface 93 of each of the rails 80 ₁, 80 ₂.Each of the lateral plates 106 ₃, 106 ₆ and each of the front connectionplates 186 ₁, 186 ₂ are fastened to the outboard lateral surfaces ofrespective ones of the rails 80 ₁, 80 ₂ and the beams 64 ₁, 64 ₂. Inthis embodiment, the transversal connection plate 174 is also fastenedto each of the lateral plates 106 ₃, 106 ₆. In this embodiment, theplates of the connection structure 185 are fastened to the rails 80 ₁,80 ₂ and the beams 64 ₁, 64 ₂ via welding, although in otherembodiments, these plates may be fastened in any other suitable way(e.g., via bolts and/or rivets).

The reinforcement arm assemblies 195 ₁, 195 ₂ are configured to supporta load induced by a tension of a track of the track assemblies 16 ₁, 16₂. Each of the reinforcement arm assemblies 195 ₁, 195 ₂ is connected tothe support members 104 ₂, 104 ₃ via a pair of beams 198, 200 that arein turn connected to a transversal reinforcement element 202 positionedin between the support members 104 ₂, 104 ₃ in the longitudinaldirection of the vehicle 10. In this embodiment, the beam 198 isfastened to the support member 104 ₂ and to the transversalreinforcement element 202, while the beam 200 is fastened to the supportmember 104 ₃ and to the transversal reinforcement element 202. The beam198 is oriented at an angle relative to the longitudinal direction ofthe vehicle 10 while the beam 200 is generally parallel to thelongitudinal direction of the vehicle 10. In this embodiment, thetransversal reinforcement element 202 consists of a cylindrical hollowmetallic member.

As will be appreciated, in this embodiment, the lower frame structure 62is connected to the upper frame structure 60 over at least the firstportion P₁ of the length L_(LF) of the lower frame structure 62. Morespecifically, in this embodiment, the front connection plates 186 ₁, 186₂ are spaced apart from the transversal connection plate 174 in thelongitudinal direction of the vehicle 10. For instance, in thisembodiment, a frontmost connection point of a front connection plate 186_(i) is spaced apart from the transversal connection plate 174 by adistance equivalent to the first portion P₁ of the length L_(LF) of thelower frame structure 62.

The front and rear drawbars 87 ₁, 87 ₂ of the lower frame structure 62are positioned at a front and rear portion of the chassis 12respectively. As more clearly shown in FIG. 6, the front drawbar 87 ₁comprises an angled plate fastened to the bottom surfaces 94 of therails 80 ₁, 80 ₂, the front connection plates 186 ₁, 186 ₂ and thebottom surfaces 67 of the beams 64 ₁, 64 ₂. As such, the front drawbar87 ₁ may be o considered as part of the connection structure 185. Therear drawbar 87 ₂ comprises a folded sheet metal structure that extendstransversally to the longitudinal direction of the vehicle 10 betweenthe rear lateral plates 106 ₁, 106 ₄ and is fastened thereto (e.g., viawelding). This may provide additional support to the rear lateral platesin 106 ₁, 106 ₄. Each of the front and rear drawbars 87 ₁, 87 ₂ maycomprise shackles for attaching a load thereto.

The chassis 12 may be configured in various other ways.

For instance, with additional reference to FIG. 43, in a variant, thelateral plates of the lower frame structure 62 may be configureddifferently. For example, the lower frame structure 62 may compriselateral plates 206 ₁-206 ₆, including a pair of rear plates 206 ₁, 206₄, a pair of middle plates 206 ₂, 206 ₅, and a pair of frontal plates206 ₃, 206 ₆. The rear plates 206 ₁, 206 ₄ are substantially similar tothe rear plates 106 ₁, 106 ₄ described above in that they comprise aplate portion and a drive wheel support structure for supporting thedrive wheel of a respective one of the track assemblies 16 ₁, 16 ₂. Themiddle plates 206 ₂, 206 ₅ and the frontal plates 206 ₃, 206 ₆ areconnected to a respective one of the rails 80 ₁, 80 ₂ (e.g., viawelding) at the top surface 93 of each rail 80 _(i).

The middle plates 206 ₂, 206 ₅ are centered in relation to the supportmember 104 ₁ in the longitudinal direction of the vehicle 10. Each ofthe middle plates 206 ₂, 206 ₅ is generally rectangular and has a lengthL_(M) that is significant in relation to the length L_(LF) of the lowerframe structure 62. For instance, a ratio L_(M)/L_(LF) of the lengthL_(M) of each middle plate 206 ₂, 206 ₅ over the length L_(LF) of thelower frame structure 62 may be at least 0.1, in some cases at least0.3, in some cases at least 0.5, and in some cases even more. The middleplates 206 ₂, 206 ₅ further comprise openings 215 for engaging afastener.

Unlike the frontal plates 106 ₃, 106 ₆ described above, the frontalplates 206 ₃, 206 ₆, which are generally rectangular, are not connectedto the upper frame structure 60. That is, the frontal plates 206 ₃, 206₆ are solely connected to the lower frame structure 62. Moreover, thefrontal plates also comprise openings 217 for engaging a fastener.

The middle plates 206 ₂, 206 ₅ and the frontal plates 206 ₃, 206 ₆ havea relatively low height. That is because, unlike the middle plates 106₂, 106 ₅ and the frontal plates 106 ₃, 106 ₆ described above, the middleplates 206 ₂, 206 ₅ and the frontal plates 206 ₃, 206 ₆ are notconnected directly to the torque box 102. Rather, the middle plates 206₂, 206 ₅ and the frontal plates 206 ₃, 206 ₆ are connected via theirrespective openings 215, 217 (e.g., via a bolted connection) to“fishplates” which can in turn be connected directly to the torque box102 or to a frame similar to a standard truck frame to which the torquebox 102 may be connected to (e.g., via rivets, bolts, and/or welding). Aratio of a height of each of the middle and frontal plates 206 ₂, 206 ₃,206 ₅, 206 ₆ over a height of each of the rails 80 ₁, 80 ₂ may be nomore than 0.4, in some cases no more than 0.2, in some cases no morethan 0.1, and in some cases even less.

In another variant, with additional reference to FIG. 44, the chassis 12may be configured such that the torque box 102 is disposed substantiallyon the rails 80 ₁, 80 ₂ of the lower frame structure 62. This may allowwider torque boxes to be secured to the lower frame structure 62 becausethey do not need to fit into a channel.

To that end, the lower frame structure 62 comprises lateral plates 306₁-306 ₈, including a pair of rear plates 306 ₁, 306 ₅, a pair of firstmiddle plates 306 ₂, 306 ₆, a pair of second middle plates 306 ₃, 306 ₇,and a pair of frontal plates 306 ₄, 306 ₈. The rear plates 306 ₁, 306 ₅are substantially similar to the rear plates 106 ₁, 106 ₄ describedabove in that they comprise a plate portion and a drive wheel supportstructure for supporting the drive wheel of a respective one of thetrack assemblies 16 ₁, 16 ₂. The first middle plates 306 ₂, 306 ₆, thesecond middle plates 306 ₃, 306 ₇ and the frontal plates 306 ₄, 306 ₈are connected to a respective one of the rails 80 ₁, 80 ₂ (e.g., viawelding) at the top surface 93 of each rail 80 _(i).

The second middle plates 306 ₃, 306 ₇ are centered in relation to andsupported by the support member 104 ₁ in the longitudinal direction ofthe vehicle 10. With additional reference to FIGS. 45 and 46, the secondmiddle plate 306 ₃ (to which the second middle plate 306 ₇ is identical)comprises an inner surface 308 and an outer surface 309 opposite theinner surface 308. The second middle plate 306 ₃ comprises first andsecond portions 310, 312 for connecting to a respective one of the rails80 ₁, 80 ₂. More specifically, the first portion 310 is fastened to aninboard one of the lateral surfaces 97 ₁, 97 ₂ of the rail 80 _(i) whilethe second portion 312 is fastened to the top surface 93 of the rail 80_(i) such that the inner surface 308 of the second middle plate 306 ₃faces the inboard lateral surface 97 _(i) and the top surface 93 of therail 80 _(i). In this example of implementation, the first and secondportions 310, 312 are connected to the rail 80 _(i) via welding.However, the first and second portions 310, 312 may be connected to therail 80 _(i) in any other suitable way (e.g., via bolts or rivets). Thesecond middle plate 306 ₃ further comprises a connecting portion 314comprising at least one opening 316 for affixing the torque box 102, andsupport flanges 318, 320, 322 projecting from the connecting portion 314to support the connecting portion 314. The support flanges 318, 320, 322are configured to provide support to the second middle plate 306 ₃. Forinstance, the support flanges 318, 320 are affixed to an outboard one ofthe lateral surfaces 97 ₁, 97 ₂ of the rail 80 _(i) (or to a reinforcingplate that is affixed to the outboard lateral surface 97 _(i) of therail 80 _(i)) while the support flange 322 is affixed to and supportedby the first support member 104 ₁. The support flanges 318, 320, 322 canbe affixed to the rail 80 _(i) or the first support member 104 ₁ viawelding or in any other suitable way (e.g., bolts or rivets).

The first middle plates 306 ₂, 306 ₆ are configured similarly to thesecond middle plates 306 ₃, 306 ₇ with the exception that they do notcomprise a portion that is affixed to an inboard one of the lateralsurfaces 97 ₁, 97 ₂ of the rail 80 _(i) and they do not comprise asupport flange that is affixed to any of the support members 104 ₁-104₃. Rather, the first middle plates 306 ₂, 306 ₆ comprise a supportflange affixed solely to the outboard one of the lateral surfaces 97 ₁,97 ₂ of the rail 80 _(i). Each of the first middle plates 306 ₂, 306 ₆comprises at least one opening 324 for affixing the torque box 102. Insome embodiments, the first and second middle plates 306 ₂, 306 ₃, 306₆, 306 ₇ and the frontal plates 306 ₄, 306 ₈ may have a thicknessbetween 0.25 inch and 1 inch.

With additional reference to FIGS. 47 and 48, the frontal plate 306 ₄(to which the frontal plate 306 ₈ is identical) comprises an innersurface 340 and an outer surface 342 opposite the inner surface 340. Thefrontal plate 306 ₄ further comprises a first portion 344 for affixingthe frontal plate 306 ₄ to the rail 80 _(i), and a connecting portion346 extending beyond the widthwise extent of the rail 80 _(i) andcomprising at least one opening 348 for affixing the torque box 102 tothe frontal plate 306 ₄. A lateral edge 349 of the frontal plate 306 ₄is affixed (e.g., via welding) to the transversal connection plate 174.The frontal plate 306 ₄ also comprises a support flange 350 projectingfrom the connecting portion 346 to support the connecting portion 346.The support flange 350 is configured to provide support to the frontalplate 306 ₄. For instance, the support flange 350 is affixed to anoutboard one of the lateral surfaces 97 ₁, 97 ₂ of the rail 80 _(i) (orto a reinforcing plate that is affixed to the outboard lateral surface97 _(i) of the rail 80 _(i)) The support flange 350 can be affixed tothe rail 80 _(i) via welding or in any other suitable way (e.g., boltsor rivets).

As shown in FIGS. 49 and 50, in this variant, the torque box 102 ismounted substantially on the rails 80 ₁, 80 ₂. That is, when the torquebox 102 is mounted to the lower frame structure 62, the bottom surface166 of the torque box 102 is separated from the top surface 93 of therails 80 ₁, 80 ₂ by no vertical gap (or by a vertical gap 375 that is ofnegligible size). More specifically, the bottom surface 166 of thetorque box 102 is in contact with the outer surface of each of the firstand second middle plates 306 ₂, 306 ₃, 306 ₆, 306 ₇ and the frontalplates 306 ₄, 306 ₈ such that the bottom surface 166 of the torque box102 is separated from the top surface 93 of each rail 80 _(i) by aspacing approximately equal to a thickness of each of the first andsecond middle plates 306 ₂, 306 ₃, 306 ₆, 306 ₇ and the frontal plates306 ₄, 306 ₈. As such, the spacing between the torque box 102 and therails 80 ₁, 80 ₂ may be no more than 4 inches, in some cases no morethan 2 inches, in some cases no more than 0.25 inch, and in some caseseven less. This may allow the work equipment 41 to be mounted on thechassis 12 at an even further lowered position to allow a greaterclearance between the work equipment 41 and the vehicle height limit ofthe public road infrastructure and/or to allow taller work equipment 41to be installed without surpassing the vehicle height limit of thepublic road infrastructure. The torque box 102 is secured to the firstand second middle plates 306 ₂, 306 ₃, 306 ₆, 306 ₇ and to the frontalplates 306 ₄, 306 ₈ by inserting a fastener 380 (e.g., a bolt) in theirrespective openings 316, 324, 348 and securing the fastener 380 with afastener-receiving element 382 (e.g., a nut or an internal thread of theopening 316, 324, 348).

Moreover, as shown in FIG. 44, the lower frame structure 62 of thechassis 12 may be reinforced further via reinforcement plates. Morespecifically, the lower frame structure 62 may comprise reinforcementplates 360, 362 affixed to outboard ones of the lateral surfaces 97 ₁,97 ₂ of the rails 80 ₁, 80 ₂. Each of the reinforcement plates 360, 362extends in the longitudinal direction of the vehicle 10 and spans atleast a majority of a length of the second portion P₂ of the lengthL_(LF) of the lower frame structure 62. In some cases, the reinforcementplates 360, 362 may form of a single continuous reinforcement plate.

Furthermore, the support members 104 ₁-104 ₃ of the chassis 12 may bereinforced via reinforcement collars 364 configured for supporting arespective support member 104 _(i). Each reinforcement collar 364comprises an annular body sized as to receive therein a respectivesupport member 104 _(i) and is affixed to an outboard one of the lateralsurfaces 97 ₁, 97 ₂ of the rails 80 ₁, 80 ₂ (e.g., via welding). In thisexample, the support members 104 ₂, 104 ₃ are reinforced via arespective reinforcement collar 364. Moreover, in this example, thetransversal reinforcement element 202 may also be reinforced via areinforcement collar 364 that supports the transversal reinforcementelement 202.

b) Power plant

The power plant 14 generates power to move the tracked utility vehicle10. To that end, the power plant 14 comprises a prime mover 17. Forexample, the prime mover 17 may comprise an internal combustion engineand/or one or more other types of motors (e.g., electric motors, etc.)for generating motive power to move the vehicle 10. In this embodiment,the power plant 14 is affixed to the first and second crossmembers 66 ₁,66 ₂ of the upper frame structure 60.

The power plant 14 is in a driving relationship with each of the trackassemblies 16 ₁, 16 ₂. That is, power derived from the power plant 14 istransmitted to each of the track assemblies 16 ₁, 16 ₂ in order to drivethe track assemblies 16 ₁, 16 ₂. In this embodiment, with additionalreference to FIGS. 24 and 25, power from the power plant 14 istransmitted to the track assemblies 16 ₁, 16 ₂ via a hydraulic drivesystem 21.

For instance, in this example, the hydraulic drive system 21 comprises,for each of the track assemblies 16 ₁, 16 ₂, a hydraulic pump 26 drivenby the prime mover 17 and connected to a hydraulic motor (not shown)which drives that track assembly. Power from the power plant 14 may betransmitted to the track assemblies 16 ₁, 16 ₂ in various other ways inother embodiments.

In this embodiment, the power plant 14 includes a housing 46 whichhouses the prime mover 17 and other components of the power plant 14.More particularly, in this embodiment, the housing 46 houses: hydrauliccomponents including each hydraulic pump 26 of the hydraulic drivesystem 21 and a hydraulic fluid reservoir; a cooling system for coolingthe prime mover 17 and hydraulic fluid of the hydraulic drive system 21;batteries; components of an exhaust system; pipes; and cables. Othercomponents of the power plant 14 may be housed in the housing 46 inother embodiments.

The housing 46 and the components of the power plant 14 that it housesare mounted on top of the upper frame structure 60. More particularly,in this embodiment, the housing 46 comprises a back housing portion 47 ₁which houses a first portion of the power plant 14 and is located abovethe upper frame structure 60 behind the operator cabin 20 and a sidehousing portion 47 ₂ which houses a second portion of the power plant 14and is located above the upper frame structure 60 on a right side of theoperator cabin 20. Thus, in this embodiment, the housing 46 has agenerally L-shaped configuration that extends behind and next to theoperator cabin 20, with the back housing portion 47 ₁ being elongated inthe widthwise direction of the vehicle 10 and the side housing portion47 ₂ being elongated in the longitudinal direction of the vehicle 10.

Mounting of the housing 46 and the components of the power plant 14 thatit houses above the upper frame structure 60 may facilitate installationand servicing of the power plant 14. For example, maintenance or otherservicing activities may be performed by accessing components of thepower plant 14 without being obstructed by the work equipment 41.

Also, components of the power plant 14, including the prime mover 17,the hydraulic pumps of the hydraulic drive system 21, and the housing46, may secured to one another to constitute a “power plant module” thatcan be installed on and removable from the chassis 12 together as aunit. This may allow the tracked utility vehicle 10 to be easilyequipped with a particular one of a plurality of different power plantmodules during manufacturing of the vehicle 10 depending on anapplication or environment in which the vehicle 10 will be used. Forexample, in some embodiments, the plurality of different power plantmodules may comprise different types of prime movers. For instance, insome cases, the different types of prime movers may be different typesof internal combustion engines, such as different types of engines thatconform to requirements of different engine tiers (e.g., an engineconforming to requirements of a T3 engine tier and an engine conformingto requirements of a T4 engine tier). In such examples ofimplementation, a controller controlling the prime mover 17 (e.g., anengine control unit (ECU)) may comprise software that can control thedifferent types of engines and receives an input indicating a particulartype of engine to which the prime mover 17 corresponds to control itaccordingly.

Furthermore, mounting of the housing 46 and the components of the powerplant 14 that it houses above the upper frame structure 60 may allow theheight H_(v) of the tracked utility vehicle 10 to be kept small. Thismay be beneficial in various cases.

For example, in this embodiment, the operator cabin 20 can have one ormore seats to accommodate a number of individuals (e.g., one, two,etc.,) as further discussed later on, and the tracked utility vehicle 10carrying the work equipment 41 can travel on a public roadinfrastructure. The vehicle 10 may travel on the public roadinfrastructure by self-propulsion or by being transported on anothervehicle (e.g., on a flatbed truck). The vehicle 10 may therefore respecta vehicle height limit (i.e., a maximum vehicle height allowable) fortravel on the public road infrastructure. The vehicle height limit isnormally set by a government responsible for the public roadinfrastructure. For example, in some cases, the vehicle height limit fortravel on the public road infrastructure may be between 13.5 feet (4.1m) and 14 feet (4.3 m). The vehicle height limit for travel on thepublic road infrastructure may have any other suitable value in othercases.

More particularly, in this embodiment, when the work equipment 41 is inthe retracted nonworking state (i.e., a state in which it is retractedonto the vehicle 10 and not performing any work operation, as opposed toan extended working state in which it is extended outwardly from thevehicle 10 to perform a work operation), the work equipment 41 isarranged such that it extends frontward in the longitudinal direction ofthe vehicle 10 beyond a rear side 114 of the operator cabin 20. In thisexample of implementation, the work equipment 41 extends frontward inthe longitudinal direction of the vehicle 10 beyond a front side 112 ofthe operator cabin 20, next to a right side 116 ₂ of the operator cabin20, above the side housing portion 47 ₂. Mounting part of the powerplant 14, including the prime mover 17, on top of the upper framestructure 60 and behind the operator cabin 20 (e.g., as opposed towithin an internal space or “tub” defined by the chassis 12) allows theoperator cabin 20 to be low enough for installing the work equipment 41in this manner. For example, in some embodiments, the height H_(v) ofthe vehicle 10 to the roof 118 of the operator cabin 20 may be no morethan 2.8 m, in some cases no more than 2.7 m, and in some cases no morethan 2.6 m. For instance, in this embodiment, the height H_(v) of thevehicle 10 may be about 2.5 m.

As another example, the tracked utility vehicle 10, without the workequipment 41 installed thereon, may fit in a closed shipping containerfor transport (e.g., overseas).

For instance, in some examples, a maximum height for a shippingcontainer may be no more than 3 m, in some cases no more than 2.8 m, andin some cases no more than 2.6 m, and the vehicle 10 may fit in thatshipping container.

As yet another example, keeping the height H_(v) of the tracked utilityvehicle 10 small may permit a vertical distance between a top of theoperator cabin 20 and the lower frame structure 62 to be identical orsimilar to a corresponding distance in trucks to allow work equipmentsuch as the work equipment 41 possibly designed primarily for mountingon trucks to be easily mountable on the vehicle 10.

In addition to generating motive power to propel the tracked utilityvehicle 10, in some embodiments, the power plant 14 may power the workequipment 41 carried by the vehicle 10. For instance, in some cases, theprime mover 17 may be used to supply power to the work equipment 41. Inother cases, the power plant 14 may comprise an additional prime moverto supply power to the work equipment 41.

c) Track Assemblies

The track assemblies 16 ₁, 16 ₂ are used to propel the tracked utilityvehicle 10 on the ground. The track assembly 16 ₁ is on a first lateralside of the vehicle 10, while the track assembly 16 ₂ is on a secondlateral side of the vehicle 10. The track assemblies 16 ₁, 16 ₂ aremounted to the lower frame structure 62. Each of the track assemblies 16₁, 16 ₂ supports a portion of a weight of the vehicle 10 in use. In thisexample, the track assemblies 16 ₁, 16 ₂ are similarly configured andare disposed symmetrically relative to the lower frame structure 62 ofthe chassis 12 and thus the portion of the weight of the vehicle 10supported by each of the track assemblies 16 ₁, 16 ₂ is about half ofthe weight of the vehicle 10. In other examples, the portion of theweight of the vehicle 10 supported by each of the track assemblies 16 ₁,16 ₂ may be other than one-half of the weight of the vehicle 10.

With additional reference to FIG. 26, in this embodiment, each trackassembly 16 _(i) comprises a plurality of wheels, which includes a drivewheel 24, an idler wheel 23 (alternatively referred to as an end wheel),and a plurality of support wheels 28 ₁-28 ₄, and an endless track 22disposed around the wheels 24, 23, 28 ₁-28 ₄. The track assembly 16 _(i)has a length L_(ta), a width W_(ta), and a height H_(ta). A longitudinaldirection of the track assembly 16 _(i) is generally parallel to thelongitudinal direction of the tracked utility vehicle 10. The trackassembly 16 _(i) also has transversal directions, including a widthwisedirection which is generally parallel to the widthwise direction of thetracked vehicle 10, and a height direction which is generally parallelto the height direction of the vehicle 10.

The endless track 22 engages the ground to provide traction. The endlesstrack 22 is disposed around the wheels 24, 23, 28 ₁-28 ₄ and includes atop run 40 and a bottom run 42. The top run 40 and the bottom run 42 ofthe endless track 22 are generally parallel to one another and extendalong the longitudinal direction of the tracked utility vehicle 10. Thetop run 40 of the endless track 22 is generally horizontal and has alength that is generally defined by the distance between the drive wheel24 and the idler wheel 23. The bottom run 42 of the endless track 22 isthat portion of the endless track 22 which is beneath the support wheels28 ₁-28 ₄ and which engages the ground. The bottom run 42 of the endlesstrack 22 has a length that is generally defined by the distance betweena frontmost one of the support wheel 28 ₁-28 ₄, in this case, thesupport wheel 28 ₁, and a rearmost one of the support wheel 28 ₁-28 ₄,in this case, the support wheel 28 ₄.

The drive wheel 24 is in a driven relationship with the power plant 14to impart movement of the endless track 22 in order to propel thevehicle 10 on the ground. The drive wheel 24 is rotatable about an axisof rotation 192 which is transverse to the longitudinal direction of thevehicle 10 by power derived from the power plant 14 to impart movementof the endless track 22. More specifically, the drive wheel 24 ismounted to the drive wheel support structure 117 via a planetary gearbox(not shown). Thus in this embodiment, the drive wheel 24 is located in arear region of the chassis 12 and therefore a powertrain of the trackedutility vehicle 10 is configured to transmit the motive power of theprime mover 17 to the rear of the vehicle 10. To that end, in thisembodiment, the powertrain of the tracked utility vehicle 10 comprises ahydrostatic transmission (not shown) which connects the hydraulic drivesystem 21 at the front of the vehicle 10 to the drive wheel 24 at therear of the vehicle 10. In this embodiment, the drive wheel 24 comprisesa sprocket that engages the endless track 22. The drive wheel 24 may beconfigured in various other ways in other embodiments.

As shown in FIG. 26, the top surface 93 of each rail 80 _(i) of thelower frame structure 62 may be positioned slightly higher than the axisof rotation 192 of the drive wheel 24 of respective ones of the trackassemblies 16 ₁, 16 ₂. For example, a distance Y₁ measured from the topsurface 93 of each rail 80 _(i) to the ground may be greater than adistance Y₂ measured from the axis of rotation 192 of the drive wheel 24to the ground. For instance, in some cases, the top surface 93 of eachrail 80 _(i) may be further from the ground than the axis of rotation192 of the drive wheel 24 by (i.e., Y₁-Y₂ may be) no more than 320 mm(about 12.6 inches), in some cases no more than 150 mm (about 5.9inches), in some cases no more than 50 mm (about 2 inches) and in somecases even less than 50 mm (e.g., 25 mm (about 1 inch)).

The idler wheel 23 does not convert power derived from the power plant14 to motive force for movement of the endless track 22, but ratherguides the endless track 22 and maintains it under tension as it isdriven by the drive wheel 24. The idler wheel 23 is rotatable about anaxis of rotation which is transverse to the longitudinal direction ofthe tracked utility vehicle 10. In this embodiment, the idler wheel 23,which is located in a rear region of the chassis 12, and morespecifically in a rear region of the lower frame structure 62 of thechassis 12, may comprise a sprocket or any other type of wheel thatengages the endless track 22.

The support wheels 28 ₁-28 ₄ are arranged in an in-line configurationextending along the longitudinal direction of tracked utility vehicle 10and roll on the bottom run 42 of the endless track 22 as the vehicle 10moves on the ground. The support wheels 28 ₁-28 ₄ do not convert powerderived from the power plant 14 to motive force for movement of theendless track 22, but rather support and distribute onto the ground viathe endless track 22 the portion of the weight of the vehicle 10 that issupported by the track assembly 16 _(i). The support wheels 28 ₁-28 ₄may also maintain the shape and position of the endless track 22, aswell as keep the track 22 generally aligned with the general directionof vehicular movement.

Each of the support wheels 28 ₁-28 ₄ occupies most of the height H_(ta)of the track assembly 16 _(i). That is, each of the support wheels 28₁-28 ₄ has a diameter D_(sw) corresponding to at least half, in somecases at least two-thirds, and in some cases at least three-quarters ofthe height H_(ta) of the track assembly 16 _(i). In this case, thediameter D_(sw) of each of the support wheels 28 ₁-28 ₄ corresponds toabout 65% of the height H_(ta) of the track assembly 16 _(i). In someembodiments, the diameter D_(sw) of each of the support wheels 28 ₁-28 ₄may be such that the top run 40 of the endless track 22 can contact thesupport wheels 28 ₁-28 ₄ in use. In other embodiments, the supportwheels 28 ₁-28 ₄ may be made smaller such that there is no contactbetween the top run 40 of the endless track 22 and the support wheels 28₁-28 ₄ in use.

The support wheels 28 ₁-28 ₄ are carried by a plurality ofwheel-carrying assemblies 50 ₁, 50 ₂ of the track assembly 16 _(i). Eachof the wheel-carrying assemblies 50 ₁, 50 ₂ carries at least two of thesupport wheels 28 ₁-28 ₄ and, since it is an assembly carrying wheels,will be referred to as a “bogie”. More particularly, in this embodiment,the bogie 50 ₁ carries the support wheels 28 ₁, 28 ₂ and the bogie 50 ₂carries the support wheels 28 ₃, 28 ₄.

With additional reference to FIGS. 26, 41 and 42, the bogie 50 ₁comprises a link 70 interconnecting the support wheels 28 ₁, 28 ₂ andpivotable relative to the lower frame structure 62 about a pivot 71which defines a pivot axis. The link 70 is a connecting structure thatmay have any suitable form (e.g., a single member or a plurality ofmembers connected to one another by one or more fasteners, welding,etc.). More specifically, the link 70 comprises an axle for mountingwithin an aperture of its corresponding support member 104 _(i). Theaxle of the link 70 may be secured to the support member 104 _(i) in anysuitable way (e.g., via fasteners). The support wheels 28 ₁, 28 ₂ arerotatably mounted to the link 70 via respective axles which definerespective axes of rotation of the support wheels 28 ₁, 28 ₂. In thisembodiment, the pivot axis of the link 70 lies closer to the axis ofrotation of the support wheel 28 ₁ than that of the support wheel 28 ₂and above the axes of rotation of the support wheels 28 ₁, 28 ₂. Thepivot axis of the link 70 and the axes of rotation of the support wheels28 ₁, 28 ₂ may be positioned differently in relation to one another inother embodiments (e.g., the pivot axis of the link 70 may lieequidistant between the axes of rotation of the support wheels 28 ₁, 28₂). The bogie 50 ₂ is configured similarly to the bogie 50 ₁ and willthus not be further discussed.

In this embodiment, each bogie 50 _(i) and the drive wheel 24 arealigned with respective ones of the lateral plates 106 ₁-106 ₆ in thelongitudinal direction of the vehicle 10. Thus, in this embodiment, aprojection of the axis of rotation of each bogie 50 _(i) intersects aprojection onto the ground plane of at least one of the lateral plates106 ₁-106 ₆. Also in this embodiment, a projection of the axis ofrotation 192 of the drive wheel 24 onto a ground plane intersects aprojection onto the ground plane of at least one of the lateral plates106 ₁-106 ₆.

The endless track 22 engages the ground to provide traction to thetracked utility vehicle 10. More particularly, as the drive wheel 24 isrotated by power derived from the power plant 14, the drive wheel 24imparts motion to the endless track 22 for traction of the vehicle 10 onthe ground. The endless track 22 has an inner side 32 facing the wheels24, 23, 28 ₁-28 ₄ and a ground-engaging outer side 33, opposite theinner side 32, for engaging the ground.

In this embodiment, as shown in FIGS. 27 and 28, the endless track 22comprises an elastomeric body 37 underlying its inner side 32 and itsground-engaging outer side 33. The body 37 is elastomeric in that itcomprises elastomeric material which allows the track 22 to elasticallychange in shape as it is in motion around the wheels 24, 23, 28 ₁-28 ₄.The elastomeric material of the body 37 can be any polymeric materialwith suitable elasticity. In this embodiment, the elastomeric materialincludes rubber. Various rubber compounds may be used and, in somecases, different rubber compounds may be present in different areas ofthe track 22. In other embodiments, the elastomeric material may includeanother elastomer in addition to or instead of rubber (e.g.,polyurethane elastomer).

A plurality of cores 21 ₁-21 _(C) are embedded in the elastomericmaterial of the body 37 of the endless track 22, spaced apart along thelongitudinal direction of the track 22, and extending transversally tothe longitudinal direction of the track 22 to impart transverse rigidityto the track 22. The cores 21 ₁-21 _(C) are made of rigid material. Forinstance, in this embodiment, the cores 21 ₁-21 _(C) are metallic (e.g.,steel) cores. This type of track can thus sometimes be referred to as a“metal-embedded rubber track” (MERT).

The cores 21 ₁-21 _(C) interact with the wheels 24, 23, 28 ₁-28 ₄ toimpart and/or guide motion of the endless track 22. For example, in thisembodiment, the track 22 has a plurality of drive openings 19 ₁-19 _(O)for receiving teeth of the drive wheel 24 such that the drive wheel 24can engage parts of the track 22 where are located individual ones ofthe cores 21 ₁-21 _(C) in order to apply motive force to the track 22.The cores 21 ₁-21 _(C) also guide motion of the track 22 as it is drivenby the drive wheel 24. More particularly, each core 21 _(i) comprises apair of wings 29 ₁, 29 ₂ and a wheel guide 25 between the wings 29 ₁, 29₂. The wheel guide 25 comprises at least one, in this case, two guideprojections 36 ₁, 36 ₂ projecting on the inner side 32 of the endlesstrack 22. In this embodiment, when its teeth enter the drive openings 19₁-19 _(O) of the track 22, the drive wheel 24 engages the wheel guide 25of the core 21 _(i) between the guide projections 36 ₁, 36 ₂ to drivethe track 22, while the guide projections 36 ₁, 36 ₂ pass in a guidingspace 38 defined by each of the support wheels 28 ₁-28 ₄ in order toguide the track 22 relative to the support wheels 28 ₁-28 ₄.

One or more reinforcements may be embedded in the elastomeric materialof the body 37 of the endless track 22. For instance, a reinforcementmay be a layer of reinforcing cables 43 ₁-43 _(R) that are adjacent toone another and that extend in the longitudinal direction of the track22 to enhance strength in tension of the track 22 along its longitudinaldirection. In some cases, a reinforcing cable 43 _(i) may be a cord orwire rope including a plurality of strands or wires. In other cases, areinforcing cable 43 _(i) may be another type of cable and may be madeof any material suitably flexible longitudinally (e.g., fibers or wiresof metal, plastic or composite material). Various other types ofreinforcements may be provided in other embodiments.

The ground-engaging outer side 33 of the endless track 22 comprises atread pattern to enhance traction on the ground. The tread patterncomprises a plurality of traction projections 49 ₁-49 _(T), which can bereferred to as “traction lugs”, spaced apart along the longitudinaldirection of the track 22 and engaging the ground to enhance traction.The ground-engaging outer side 33 of the track 22 also comprises aground-engaging surface 190 in between the traction projections 49 ₁-49_(T).

As shown in FIG. 38, in this embodiment, the top surface 93 of each rail80 _(i) of the lower frame structure 62 is positioned closer to theground than the ground-engaging surface 190 of the top run 40 of thetrack 22 of respective ones of the track assemblies 16 ₁, 16 ₂. Forinstance, a distance H₁ measured from the ground-engaging surface 190 ofthe top run 40 of the track 22 to the ground is greater than a distanceH₂ measured from the top surface 93 of the rails 80 ₁, 80 ₂ to theground. For example, in some cases, the top surface 93 of each rail 80_(i) is closer to the ground than the ground-engaging surface 190 of thetop run 40 of each track 22 by (i.e., H₁-H₂ may be) at least 90 mm(about 3.5 inches), in some cases by at least 300 mm (about 11.8inches), in some cases by at least 500 mm (about 19.7 inches), and insome cases by at least 640 mm (about 25.2 inches).

The distance H₂ itself (i.e., the distance H₂ measured from the topsurface 93 of the rails 80 ₁, 80 ₂ to the ground) may in someembodiments be 16 inches, in other non-limiting embodiments 28 inchesand in still other embodiments, 42 inches, or even more.

The inner side 32 of the endless track 22 comprises the guideprojections 36 ₁, 36 ₂ of each of the cores 21 ₁-21 _(C). In addition,the inner side 32 of the track 22 comprises rolling surfaces 39 ₁, 39 ₂on which the support wheels 28 ₁-28 ₄ roll to apply the track 22 ontothe ground.

The endless track 22 may be configured in various other ways in otherembodiments.

For example, in some embodiments, as shown in FIGS. 29 and 30, theendless track 22 may comprise a pair of belts 30 ₁, 30 ₂ spaced apart toaccommodate the wheels 24, 23, 28 ₁-28 ₄ and a series of cross-links 31₁-31 _(N) distributed longitudinally along the track 22 and extendingtransversally to interconnect the belts 30 ₁, 30 ₂.

Each belt 30 _(i) is elastomeric in that it comprises rubber and/orother elastomeric material. The belt 30 _(i) may comprise one or morereinforcements such as a layer of cables embedded in its rubber and/orother elastomeric material. In this case, the belt 30 _(i) is made up ofa series of belt sections connected to one another. In other cases, thebelt 30 _(i) may be a one-piece belt.

The cross-links 31 ₁-31 _(N) interconnect the belts 30 ₁, 30 ₂ andinteract with the wheels 24, 23, 28 ₁-28 ₄ as the endless track 22 movesaround these wheels. For example, in this embodiment, as the drive wheel24 rotates, individual ones of the cross-links 31 ₁-31 _(N) engagerecesses between the teeth of the drive wheel 24, thereby causing thetrack 22 to be driven. Also, the cross-links 31 ₁-31 _(N) help to guidemotion of the track 22 by contacting the support wheels 28 ₁-28 ₄. Moreparticularly, each cross-link 31 _(i) comprises a wheel guide 44including a pair of guide projections 45 ₁, 45 ₂ projecting on the innerside 32 of the endless track 22. In this embodiment, when its teethenter gaps between the cross-links 31 ₁-31 _(N), the drive wheel 24engages the wheel guide 44 of the cross-links 28 ₁-28 ₄ between theguide projections 45 ₁, 45 ₂ to drive the track 22, while the supportwheels 28 ₁-28 ₄ pass between the guide projections 45 ₁, 45 ₂ in orderto guide the track 22 relative to the support wheels 28 ₁-28 ₄. In suchembodiments, each of the support wheels 28 ₁-28 ₄ may be a unitarysupport wheel as shown in FIG. 31.

Each cross-link 31 _(i) comprises an elongated member 73 extendingtransversally to the longitudinal direction of the endless track 22 tointerconnect the belts 30 ₁, 30 ₂. The elongated member 73 is made ofrigid material, in this case metallic material (e.g., steel). Theelongated member 73 is secured to the belts 30 ₁, 30 ₂ by fastenerswhich extend through the elongated member 73, the belts 30 ₁, 30 ₂, andbacking plates 75 ₁, 75 ₂ disposed on the inner side 32 of the track 22.In this embodiment, the cross-link 31 ₁ comprises a polymeric sole 77mounted to the elongated member 73. The polymeric sole 77 can be usedwhen the vehicle 10 is to travel on a hard surface (e.g., a pavedsurface) in order to minimize an impact of the cross-link 31 _(i) onthat surface. In other embodiments, the cross-link 31 _(i) may notinclude any polymeric sole.

As another example, in some embodiments, the endless track 22 maycomprise an endless elastomeric body underlying its inner side 32 andits ground-engaging outer side 33, similar to the elastomeric body 37discussed above in respect of FIGS. 27 and 28, but without coresembedded in the elastomeric body (e.g., an “all-rubber” track).

The track assembly 16 _(i) comprises a track tensioner 85 formaintaining tension of the endless track 22. In this embodiment, asshown in FIGS. 41 and 42, the track tensioner 85 is connected betweenthe transversal reinforcement element 202 and the axle of the idlerwheel 23 to urge the idler wheel 23 in a direction to maintain thetension of the endless track 22. Also, in this embodiment, the tracktensioner 85 is a fluidic tensioning system, e.g., a hydraulic orpneumatic tensioning system, which comprises a piston-cylindertensioning actuator 79 connected to a fluid reservoir. In this exampleof implementation, the tensioning actuator 79 is a hydraulicpiston-cylinder actuator.

More particularly, in this embodiment, with additional reference toFIGS. 32 and 33, the tensioning actuator 79 is connected at one end tothe transversal reinforcement element 202 and at another end to an idlerwheel support arm 83 which is pivotable about a the support member 104₃. The axle of the idler wheel 23 is fixed to the idler wheel supportarm 83. The tensioning actuator 79 can apply the tension in the track 22by extending or retracting to turn the idler wheel support arm 83 aboutthe support member 104 ₃ and thus move the idler wheel 23 further orcloser to the drive wheel 24.

In this embodiment, the track tensioner 85 becomes active when thetracked utility vehicle 10 is started. That is, the track tensioner 85applies a force to generate the tension in the endless track 22 when theprime mover 17 of the vehicle 10 is started.

With additional reference to FIG. 34, in this embodiment, the tracktensioner 85 is hydraulically connected to the hydraulic drive system 21of the vehicle 10 such that the tension in the endless track 22 isgenerated by the hydraulic fluid of the hydraulic drive system 21. Thetensioning actuator 79 is in hydraulic communication with the hydraulicdrive system 21 such that, when the prime mover 17 is started and startsto power the hydraulic drive system 21, the hydraulic fluid of thehydraulic drive system 21 acts on the tensioning actuator 79, whichapplies a force to generate the tension in the endless track 22.

More particularly, as shown in FIG. 35, in this embodiment, thehydraulic drive system 21 comprises a charge pump 27 hydraulicallyconnected to the tensioning actuator 79 via a track tensioner hydrauliccircuit 13.

Although in this embodiment the track tensioner 85 is hydraulicallyconnected to the hydraulic drive system 21 of the vehicle 10 via thecharge pump 27 such that the tension in the endless track 22 isgenerated when the prime mover 17 is started and starts to power thehydraulic drive system 21, the track tensioner 85 may be connected inother ways such that it would become active when the vehicle 10 isstarted (e.g., there may be a dedicated pump for the track tensioner85).

The track assembly 16; may be configured in various other ways in otherembodiments. For example, although in this embodiment it comprises four(4) support wheels 28 ₁-28 ₄, the track assembly 16 _(i) may comprisemore than four support wheels (e.g., five (5) support wheels) in otherembodiments. As another example, while in this embodiment the drivewheel 24 is located in a front region of the lower frame structure 62and the idler wheel 23 is located in a rear region of the lower framestructure 62, this may be reversed in other embodiments such that thedrive wheel 24 is located in a rear region of the lower frame structure62 and the idler wheel 23 of the track assembly 16 _(i) is located in afront region of the lower frame structure 62. As yet another example,while in this embodiment the idler wheel 23 is not in a drivenrelationship with the power plant 14, in other embodiments, the idlerwheel 23 may be replaced by another drive wheel that is in a drivenrelationship with the power plant 14.

d) Operator Cabin

The operator cabin 20 is where an operator sits and controls the trackedutility vehicle 10. In this embodiment, the operator cabin 20 is affixedto the first and second crossmembers 66 ₁, 66 ₂ of the upper framestructure 60 and comprises a front side 112, a rear side 114, a pair oflateral sides 116 ₁, 116 ₂, a roof 118, and a floor 120. The lateralside 116 ₁ of the operator cabin 20 defines an access opening 122 thatcan be closed by a door 124 and that allows the operator to enter orexit the operator cabin 20. A plurality of windows 126 ₁-126 _(W) areprovided to allow the operator to see outside of the vehicle 10.

In this embodiment, with additional reference to FIG. 39, the topsurface 93 of each rail 80 _(i) of the pair of parallel rails 80 ₁, 80 ₂is positioned closer to the ground than the floor of the operator cabin20. For instance, a distance Z₁ measured from the floor 120 of theoperator cabin 20 to the ground may be greater than a distance Z₂measured from the top surface 93 of each rail 80 _(i) to the ground. Forexample, the top surface 93 of each rail 80 _(i) may be closer to theground than the floor 120 of the operator cabin 20 by (i.e., Z₁-Z₂ maybe) at least 300 mm (about 11.8 inches), in some cases by at least 450mm (about 17.7 inches), in some cases by a least 550 mm (about 21.7inches) and in some cases by even more than 550 mm (e.g., 600 mm (about23.6 inches)).

As another example, in this embodiment, even when the torque box 102 ismounted to the lower frame structure 62, the top surface 164 of thetorque box 102 is still closer to the ground than the floor of theoperator cabin 20. For instance, the distance Z₁ measured from the floor120 of the operator cabin 20 to the ground may be greater than adistance Z₃ measured from the top surface 164 of the torque box 102 tothe ground. For example, the top surface 164 of the torque box 102 maybe closer to the ground than the floor 120 of the operator cabin 20 by(i.e., Z₁-Z₃ may be) at least 200 mm (about 7.9 inches), in some casesby at least 350 mm (about 13.8 inches), in some cases by a least 500 mm(about 19.7 inches) and in some cases by even more than 500 mm (e.g.,550 mm (about 21.7 inches) or more).

With additional reference to FIG. 36, the operator cabin 20 comprises aseating area 132 and a user interface 130.

The user interface 130 enables the operator to interact with the trackedutility vehicle 10. For example, the user interface 130 comprisescontrols allowing the operator to move the tracked utility vehicle 10 onthe ground. In some cases, the user interface 130 may also includecontrols for controlling the work equipment 41 carried by the vehicle10. The user interface 130 comprises an input portion to allow theoperator to input commands for execution by the vehicle 10 and an outputportion to convey information to the operator.

In this embodiment, the input portion of the user interface 130comprises an accelerator 133, a steering device 134, a transmissionstate selector 135, a starter switch 137, and a control lever 138. Moreparticularly:

-   -   The accelerator 133 allows the operator to control a speed of        the vehicle 10 on the ground. In this example, the accelerator        133 comprises a speed pedal operated by a foot of the operator.        The accelerator 133 may be implemented in other ways in other        examples (e.g., a hand-operated accelerator).    -   The steering device 134 allows the operator to steer the vehicle        10 on the ground. In this example, the steering device 134        comprises a steering wheel that is rotatable relative to a        steering column 144 about a steering axis. In addition to the        steering wheel 134, in this example of implementation, the        steering column 144 supports the transmission state selector        135, the starter switch 137, and the control lever 138. The        steering device 134 may be implemented in other ways in other        embodiments (e.g., a joystick).    -   The transmission state selector 135 allows the operator to        control a state of power transmission to the track assemblies 16        ₁, 16 ₂. For instance, in this example, the transmission state        selector 135 comprises a proportional front-neutral-reverse        selector to control whether power is transmitted to the track        assemblies 16 ₁, 16 ₂ to move in a forward or reverse direction        or not transmitted to the track assemblies 16 ₁, 16 ₂. The        transmission state selector 135 may be implemented in other ways        in other embodiments.    -   The starter switch 137 allows the operator to start the prime        mover 17 of the vehicle 10. For instance, in this example, the        starter switch 137 comprises a key-receiving unit to receive a        key to start the prime mover 17 of the vehicle 10. The starter        switch 137 may be implemented in other ways in other embodiments        (e.g., a start button, a code entry device, a biometric        authentication device, etc.).    -   The control lever 138 allows the operator to control various        devices of the vehicle 10. For instance, in this example, the        control lever 138 includes a wiper control which allows the        operator to control a wiper 140 of the front window 126 ₁ of the        operator cabin 20, a washer fluid control which allows the        operator to control outflow of washer fluid from a washer fluid        nozzle onto the front window 126 ₁, and a turning indicator        control which allows the operator to control a turning indicator        of the vehicle 10. The control lever 138 may include any other        suitable control in other examples.

The input portion of the user interface 130 may comprise any other inputdevice (e.g., a set of buttons, a joystick, a trackball, etc.) in otherembodiments.

In this embodiment, the output portion of the user interface 130comprises a display 140 to visually convey information to the operator.The display 140 may be any suitable type of electronic display (e.g., aliquid-crystal display (LCD), etc.). Various information can be conveyedto the operator on the display 140. For example, in some embodiments,the display 140 may implement an instrument panel that provides: aspeedometer indicator which conveys information indicative of the speedat which the vehicle 10 is moving as measured by a speedometer of thevehicle 10; a tachometer indicator which conveys information indicativeof the speed at which the prime mover 17 is running as measured by atachometer of the vehicle 10; an odometer indicator which conveysinformation indicative of a distance traveled by the vehicle 10 asmeasured by an odometer of the vehicle 10; a fuel gauge indicator whichconveys information indicative of a quantity of fuel remaining in thevehicle 10; and/or any other indicator conveying information to theuser. Each of the speedometer indicator, the tachometer indicator, theodometer indicator, and/or other indicators may comprise a digitalnumerical reading, a digital dial, a digital bar graph, a digitalsymbol, and/or any other element displayable on the display 140 toconvey information to the operator.

The output portion of the user interface 130 may comprise any otheroutput device (e.g., one or more mechanical dials (e.g., a speedometerdial, a fuel gauge dial, etc.) or other mechanical indicators (e.g., amechanical odometer); one or more light indicators (e.g., low fuel lightindicator, etc.); a speaker; etc.) in other embodiments.

The user interface 130 is connected to other components of the trackedutility vehicle 10 to cause execution of commands provided by theoperator and to present information to the operator. More particularly,in this embodiment, there are a plurality of connections 142 ₁-142 _(C)between the user interface 130 and other components of the vehicle 10.These connections 142 ₁-142 _(C) may comprise one or more mechanicallinks, wires, cables, wireless links, and/or other connecting elementsdepending on how the user interface 130 is connected to other componentsof the vehicle 10 (e.g., via mechanical control systems and/or viaelectromechanical systems (e.g., “drive-by-wire” systems)). For example,with additional reference to FIG. 37, in this embodiment:

-   -   The connection 142 ₁ is between the speed pedal 133 and the        prime mover 17. For instance, in this embodiment, the connection        142 ₁ may comprise a wire connected to a pedal position sensor        (e.g., comprising a potentiometer) for sensing a position of the        speed pedal 133 and transmitting a signal indicative of this        position to a powertrain controller 147 controlling the prime        mover 17 (e.g., an engine control unit (ECU)). In other        embodiments, the connection 142 ₁ may comprise a mechanical link        between the speed pedal 133 and a throttle for the prime mover        17.    -   The connection 142 ₂ is between the steering wheel 134 and a        steering controller 143 which controls a steering direction of        the vehicle 10 by controlling the hydraulic motors of the        hydraulic drive system 21 to cause the endless track 22 of one        of the track assemblies 16 ₁, 16 ₂ to move faster than the        endless track 22 of the other one of the track assemblies 16 ₁,        16 ₂ when the vehicle 10 turns. For instance, in this        embodiment, the connection 142 ₂ comprises a steering device        angle sensor for sensing an angle in which the steering wheel        134 is positioned and transmitting a signal indicative of this        angle to the steering controller 143.    -   The connection 142 ₃ is between the proportional        front-neutral-reverse selector 135 and the powertrain controller        147. For instance, in this embodiment, the connection 142 ₃ may        comprise a wire transmitting a signal indicative of the state of        the selector 135 to the powertrain controller 147.    -   The connection 142 ₄ is between the starter switch 137 and the        prime mover 17. For instance, in this embodiment, the connection        142 ₄ may comprise a wire between the starter switch 137 and the        powertrain controller 147.    -   The connections 142 ₅-142 _(C) are between the control lever 138        and the wiper 140, the washer fluid nozzle, the turning        indicator 141 and/or any other device of the vehicle 10 which        can be controlled via inputs at the control lever 138. For        instance, in this embodiment, the connections 142 ₆-142 _(N) may        comprise wires between the control lever 138 and an outside        functionality controller 149 of the vehicle 10 which sends        signals to these devices of the vehicle 10 to control these        devices. In other embodiments, the connections 142 ₆-142 _(N)        may comprise wires directly connected to these devices.

Controllers of the tracked utility vehicle 10, such as the powertraincontroller 147, the steering controller 143 and the outsidefunctionality controller 149, with which the user interface 130 mayinteract may be implemented in various manners. A controller comprisessuitable hardware and/or software (e.g., firmware) implementing: aninterface for receiving and transmitting signals to other components ofthe vehicle 10 to which it is connected; a processing portion comprisingone or more processors for performing processing operations, where aprocessor may be a general-purpose processor executing program codestored in the controller or a specific-purpose processor comprising oneor more preprogrammed hardware or firmware elements (e.g.,application-specific integrated circuits (ASICs), electrically erasableprogrammable read-only memories (EEPROMs), etc.); and a memory portioncomprising one or more memories for storing program code executed by theprocessing portion and/or data used during operation of the processingportion, where a memory may be a semiconductor memory (e.g., read-onlymemory (ROM) and/or random-access memory (RAM)), a magnetic storagemedium, an optical storage medium, and/or any other suitable type ofmemory. In some embodiments, two (2) or more (e.g., all) controllers ofthe vehicle 10 may be physically distinct from one another and may beconnected to one another via a bus (e.g., a controller-area network(CAN) bus or other suitable bus). In other embodiments, two (2) or more(e.g., all) controllers of the vehicle 10 may be functional entities ofa single physical control unit (e.g., a vehicle controller).

The seating area 132 comprises a seat 150 for the operator of thetracked utility vehicle 10. The seat 150, which will be referred to asan “operator seat”, is positioned relative to the user interface 130 toallow the operator to easily interact with the user interface 130.

Although the operator cabin 20 is described and depicted as having aone-person cabin configuration, in some embodiments, the operator cabin20 may have a two-person cabin configuration (i.e., a cabinconfiguration adapted to fit two persons). For example, in suchembodiments, the operator cabin 20 may comprise a passenger seatpositioned next to the operator seat 150 for sitting a passenger.

While in embodiments considered above the tracked vehicle 10 is atracked carrier vehicle carrying work equipment, in other embodiments,certain features of the tracked vehicle 10 may be implemented in othertypes of industrial tracked vehicles, such as an agricultural vehicle(e.g., a tractor, a harvester, etc.) or a construction vehicle (e.g., aloader, a bulldozer, an excavator, etc.).

Any feature of any embodiment discussed herein may be combined with anyfeature of any other embodiment discussed herein in some examples ofimplementation.

Although various embodiments have been illustrated, this was for thepurpose of describing, but not limiting, the invention. Variousmodifications will become apparent to those skilled in the art and arewithin the scope of this invention, which is defined by the followingclaims.

1. A method for providing a tracked vehicle, the method comprising:providing a chassis comprising an upper frame structure connected to alower frame structure, an operator cabin mounted to the upper framestructure, and a power plant mounted to the upper frame structure, thepower plant comprising a prime mover, wherein the lower frame structurespans a longitudinal distance along a longitudinal direction of thetracked vehicle, wherein over a first portion of the longitudinaldistance, the lower frame structure overlaps with the upper framestructure, wherein over a second portion of the longitudinal distance,the lower frame structure does not overlap with the upper framestructure, wherein the lower frame structure includes a pair of parallelelongated structural members extending along at least the second portionof the longitudinal distance spanned by the lower frame structure, andwherein the lower frame structure comprises support members extendingtransversely between the structural members; and mounting a plurality oftrack assemblies for traction of the tracked vehicle to the lower framestructure of the chassis, a first one of the track assemblies beingmounted on a first lateral side of the tracked vehicle, a second one ofthe track assemblies being mounted on a second lateral side of thetracked vehicle, each track assembly of the plurality of trackassemblies comprising: i) a plurality of wheels including: a drivewheel; an end wheel spaced apart from the drive wheel in thelongitudinal direction of the tracked vehicle; and a plurality ofsupport wheels arranged between the drive wheel and the end wheel; andii) an endless track disposed around the plurality of wheels forengaging a ground on which the tracked vehicle travels, the drive wheelbeing in driving engagement with the endless track to impart motion tothe endless track.
 2. A method comprising: providing a chassis for atracked vehicle having an operator cabin, the chassis comprising: afirst portion directly under the operator cabin; a second portion behindthe operator cabin in a longitudinal direction, the second portion beinglower to the ground than the first portion, the first portion beingreinforced so as to provide a greater resistance to torsion than thesecond portion.
 3. The method defined in claim 1, further comprisingmounting an equipment-mounting platform to the lower frame structure. 4.The method defined in claim 1, further comprising mounting a torque boxto the lower frame structure.
 5. The method defined in claim 1, furthercomprising mounting an equipment-mounting platform to the lower framestructure and mounting the work equipment to the platform.
 6. The methoddefined in claim 1, further comprising mounting work equipment to thelower frame structure via a torque box.
 7. The method defined in claim1, further comprising mounting work equipment to the lower framestructure.
 8. The method defined in claim 2, further comprising:mounting a plurality of track assemblies to the structure of thechassis, a first one of the track assemblies being mounted on a firstlateral side of the tracked vehicle, a second one of the trackassemblies being mounted on a second lateral side of the trackedvehicle, each track assembly of the plurality of track assembliescomprising: i) a plurality of wheels including: a drive wheel; an endwheel spaced apart from the drive wheel in the longitudinal direction ofthe tracked vehicle; and a plurality of support wheels arranged betweenthe drive wheel and the end wheel; and ii) an endless track disposedaround the plurality of wheels for engaging a ground on which thetracked vehicle travels, the drive wheel being in driving engagementwith the endless track to impart motion to the endless track.
 9. Themethod defined in claim 8, wherein mounting the plurality of trackassemblies for traction of the tracked vehicle to the structure of thechassis comprises mounting the plurality of track assemblies fortraction of the tracked vehicle to a lower frame structure of thechassis.
 10. The method defined in claim 2, further comprising mountingan equipment-mounting platform to the second portion.
 11. The methoddefined in claim 2, further comprising mounting a torque box to thesecond portion.
 12. The method defined in claim 2, further comprisingmounting an equipment-mounting platform to the second portion andmounting the work equipment to the platform.
 13. The method defined inclaim 2, further comprising mounting work equipment to the secondportion via a torque box.
 14. The method defined in claim 2, furthercomprising mounting work equipment to the second portion.
 15. A method,comprising: providing a vehicle that comprises: a chassis comprising anupper frame structure connected to a lower frame structure, the lowerframe structure spanning a longitudinal distance along a longitudinaldirection of the tracked vehicle, wherein: the lower frame structureincludes a pair of parallel elongated structural members extending alongthe longitudinal distance, each of the structural members having a topsurface; over a first portion of the longitudinal distance, the lowerframe structure is overlapped by the upper frame structure; and over atleast a second portion of the longitudinal distance, the lower framestructure is not overlapped by the upper frame structure; an operatorcabin mounted to the upper frame structure, wherein the chassis extendsin the longitudinal direction towards a front of the tracked vehicle toa further extent than the operator cabin; a power plant mounted to theupper frame structure and comprising a prime mover; and a plurality oftrack assemblies for traction of the tracked vehicle, a first one of thetrack assemblies being on a first lateral side of the tracked vehicle, asecond one of the track assemblies being on a second lateral side of thetracked vehicle, each track assembly of the plurality of trackassemblies being mounted to the lower frame structure and comprising: i)a plurality of wheels including: a drive wheel; an end wheel spacedapart from the drive wheel in the longitudinal direction of the trackedvehicle; and a plurality of support wheels arranged between the drivewheel and the end wheel; and ii) an endless track disposed around theplurality of wheels, the drive wheel being in driving engagement withthe endless track to impart motion to the endless track, wherein theendless track has an inner surface and an outer surface, wherein at anygiven time a portion of the endless track is located directly above thesupport wheels, wherein the outer surface of said portion of the endlesstrack is further from a ground than the top surface of each of thestructural members; and mounting work equipment to the vehicle.
 16. Themethod defined in claim 15, wherein mounting the work equipment to thevehicle comprises mounting the work equipment to the lower framestructure of the chassis.
 17. The method defined in claim 15, whereinmounting the work equipment to the vehicle comprises mounting the workequipment to the top surface of the structural members of the lowerframe structure.
 18. The method defined in claim 15, wherein mountingthe work equipment to the vehicle comprises securing a platform to thelower frame structure of the chassis and mounting the work equipment toplatform.
 19. The method defined in claim 15, wherein mounting the workequipment to the vehicle comprises securing a torque box to the lowerframe structure of the chassis and mounting the work equipment to torquebox.